diff --git a/pySim/commands.py b/pySim/commands.py
index 674e184..20b9c44 100644
--- a/pySim/commands.py
+++ b/pySim/commands.py
@@ -26,554 +26,574 @@
 from pySim.utils import rpad, b2h, h2b, sw_match, bertlv_encode_len, Hexstr, h2i, str_sanitize
 from pySim.exceptions import SwMatchError
 
+
 class SimCardCommands(object):
-	def __init__(self, transport):
-		self._tp = transport
-		self.cla_byte = "a0"
-		self.sel_ctrl = "0000"
+    def __init__(self, transport):
+        self._tp = transport
+        self.cla_byte = "a0"
+        self.sel_ctrl = "0000"
 
-	# Extract a single FCP item from TLV
-	def __parse_fcp(self, fcp):
-		# see also: ETSI TS 102 221, chapter 11.1.1.3.1 Response for MF,
-		# DF or ADF
-		from pytlv.TLV import TLV
-		tlvparser = TLV(['82', '83', '84', 'a5', '8a', '8b', '8c', '80', 'ab', 'c6', '81', '88'])
+    # Extract a single FCP item from TLV
+    def __parse_fcp(self, fcp):
+        # see also: ETSI TS 102 221, chapter 11.1.1.3.1 Response for MF,
+        # DF or ADF
+        from pytlv.TLV import TLV
+        tlvparser = TLV(['82', '83', '84', 'a5', '8a', '8b',
+                        '8c', '80', 'ab', 'c6', '81', '88'])
 
-		# pytlv is case sensitive!
-		fcp = fcp.lower()
+        # pytlv is case sensitive!
+        fcp = fcp.lower()
 
-		if fcp[0:2] != '62':
-			raise ValueError('Tag of the FCP template does not match, expected 62 but got %s'%fcp[0:2])
+        if fcp[0:2] != '62':
+            raise ValueError(
+                'Tag of the FCP template does not match, expected 62 but got %s' % fcp[0:2])
 
-		# Unfortunately the spec is not very clear if the FCP length is
-		# coded as one or two byte vale, so we have to try it out by
-		# checking if the length of the remaining TLV string matches
-		# what we get in the length field.
-		# See also ETSI TS 102 221, chapter 11.1.1.3.0 Base coding.
-		exp_tlv_len = int(fcp[2:4], 16)
-		if len(fcp[4:]) // 2 == exp_tlv_len:
-			skip = 4
-		else:
-			exp_tlv_len = int(fcp[2:6], 16)
-			if len(fcp[4:]) // 2 == exp_tlv_len:
-				skip = 6
+        # Unfortunately the spec is not very clear if the FCP length is
+        # coded as one or two byte vale, so we have to try it out by
+        # checking if the length of the remaining TLV string matches
+        # what we get in the length field.
+        # See also ETSI TS 102 221, chapter 11.1.1.3.0 Base coding.
+        exp_tlv_len = int(fcp[2:4], 16)
+        if len(fcp[4:]) // 2 == exp_tlv_len:
+            skip = 4
+        else:
+            exp_tlv_len = int(fcp[2:6], 16)
+            if len(fcp[4:]) // 2 == exp_tlv_len:
+                skip = 6
 
-		# Skip FCP tag and length
-		tlv = fcp[skip:]
-		return tlvparser.parse(tlv)
+        # Skip FCP tag and length
+        tlv = fcp[skip:]
+        return tlvparser.parse(tlv)
 
-	# Tell the length of a record by the card response
-	# USIMs respond with an FCP template, which is different
-	# from what SIMs responds. See also:
-	# USIM: ETSI TS 102 221, chapter 11.1.1.3 Response Data
-	# SIM: GSM 11.11, chapter 9.2.1 SELECT
-	def __record_len(self, r) -> int:
-		if self.sel_ctrl == "0004":
-			tlv_parsed = self.__parse_fcp(r[-1])
-			file_descriptor = tlv_parsed['82']
-			# See also ETSI TS 102 221, chapter 11.1.1.4.3 File Descriptor
-			return int(file_descriptor[4:8], 16)
-		else:
-			return int(r[-1][28:30], 16)
+    # Tell the length of a record by the card response
+    # USIMs respond with an FCP template, which is different
+    # from what SIMs responds. See also:
+    # USIM: ETSI TS 102 221, chapter 11.1.1.3 Response Data
+    # SIM: GSM 11.11, chapter 9.2.1 SELECT
+    def __record_len(self, r) -> int:
+        if self.sel_ctrl == "0004":
+            tlv_parsed = self.__parse_fcp(r[-1])
+            file_descriptor = tlv_parsed['82']
+            # See also ETSI TS 102 221, chapter 11.1.1.4.3 File Descriptor
+            return int(file_descriptor[4:8], 16)
+        else:
+            return int(r[-1][28:30], 16)
 
-	# Tell the length of a binary file. See also comment
-	# above.
-	def __len(self, r) -> int:
-		if self.sel_ctrl == "0004":
-			tlv_parsed = self.__parse_fcp(r[-1])
-			return int(tlv_parsed['80'], 16)
-		else:
-			return int(r[-1][4:8], 16)
+    # Tell the length of a binary file. See also comment
+    # above.
+    def __len(self, r) -> int:
+        if self.sel_ctrl == "0004":
+            tlv_parsed = self.__parse_fcp(r[-1])
+            return int(tlv_parsed['80'], 16)
+        else:
+            return int(r[-1][4:8], 16)
 
-	def get_atr(self) -> str:
-		"""Return the ATR of the currently inserted card."""
-		return self._tp.get_atr()
+    def get_atr(self) -> str:
+        """Return the ATR of the currently inserted card."""
+        return self._tp.get_atr()
 
-	def try_select_path(self, dir_list):
-		""" Try to select a specified path
+    def try_select_path(self, dir_list):
+        """ Try to select a specified path
 
-		Args:
-			dir_list : list of hex-string FIDs
-		"""
+        Args:
+                dir_list : list of hex-string FIDs
+        """
 
-		rv = []
-		if type(dir_list) is not list:
-			dir_list = [dir_list]
-		for i in dir_list:
-			data, sw = self._tp.send_apdu(self.cla_byte + "a4" + self.sel_ctrl + "02" + i)
-			rv.append((data, sw))
-			if sw != '9000':
-				return rv
-		return rv
+        rv = []
+        if type(dir_list) is not list:
+            dir_list = [dir_list]
+        for i in dir_list:
+            data, sw = self._tp.send_apdu(
+                self.cla_byte + "a4" + self.sel_ctrl + "02" + i)
+            rv.append((data, sw))
+            if sw != '9000':
+                return rv
+        return rv
 
-	def select_path(self, dir_list):
-		"""Execute SELECT for an entire list/path of FIDs.
+    def select_path(self, dir_list):
+        """Execute SELECT for an entire list/path of FIDs.
 
-		Args:
-			dir_list: list of FIDs representing the path to select
+        Args:
+                dir_list: list of FIDs representing the path to select
 
-		Returns:
-			list of return values (FCP in hex encoding) for each element of the path
-		"""
-		rv = []
-		if type(dir_list) is not list:
-			dir_list = [dir_list]
-		for i in dir_list:
-			data, sw = self.select_file(i)
-			rv.append(data)
-		return rv
+        Returns:
+                list of return values (FCP in hex encoding) for each element of the path
+        """
+        rv = []
+        if type(dir_list) is not list:
+            dir_list = [dir_list]
+        for i in dir_list:
+            data, sw = self.select_file(i)
+            rv.append(data)
+        return rv
 
-	def select_file(self, fid:str):
-		"""Execute SELECT a given file by FID.
+    def select_file(self, fid: str):
+        """Execute SELECT a given file by FID.
 
-		Args:
-			fid : file identifier as hex string
-		"""
+        Args:
+                fid : file identifier as hex string
+        """
 
-		return self._tp.send_apdu_checksw(self.cla_byte + "a4" + self.sel_ctrl + "02" + fid)
+        return self._tp.send_apdu_checksw(self.cla_byte + "a4" + self.sel_ctrl + "02" + fid)
 
-	def select_adf(self, aid:str):
-		"""Execute SELECT a given Applicaiton ADF.
+    def select_adf(self, aid: str):
+        """Execute SELECT a given Applicaiton ADF.
 
-		Args:
-			aid : application identifier as hex string
-		"""
+        Args:
+                aid : application identifier as hex string
+        """
 
-		aidlen = ("0" + format(len(aid) // 2, 'x'))[-2:]
-		return self._tp.send_apdu_checksw(self.cla_byte + "a4" + "0404" + aidlen + aid)
+        aidlen = ("0" + format(len(aid) // 2, 'x'))[-2:]
+        return self._tp.send_apdu_checksw(self.cla_byte + "a4" + "0404" + aidlen + aid)
 
-	def read_binary(self, ef, length:int=None, offset:int=0):
-		"""Execute READD BINARY.
+    def read_binary(self, ef, length: int = None, offset: int = 0):
+        """Execute READD BINARY.
 
-		Args:
-			ef : string or list of strings indicating name or path of transparent EF
-			length : number of bytes to read
-			offset : byte offset in file from which to start reading
-		"""
-		r = self.select_path(ef)
-		if len(r[-1]) == 0:
-			return (None, None)
-		if length is None:
-			length = self.__len(r) - offset
-		if length < 0:
-			return (None, None)
+        Args:
+                ef : string or list of strings indicating name or path of transparent EF
+                length : number of bytes to read
+                offset : byte offset in file from which to start reading
+        """
+        r = self.select_path(ef)
+        if len(r[-1]) == 0:
+            return (None, None)
+        if length is None:
+            length = self.__len(r) - offset
+        if length < 0:
+            return (None, None)
 
-		total_data = ''
-		chunk_offset = 0
-		while chunk_offset < length:
-			chunk_len = min(255, length-chunk_offset)
-			pdu = self.cla_byte + 'b0%04x%02x' % (offset + chunk_offset, chunk_len)
-			try:
-				data, sw = self._tp.send_apdu_checksw(pdu)
-			except Exception as e:
-				raise ValueError('%s, failed to read (offset %d)' % (str_sanitize(str(e)), offset))
-			total_data += data
-			chunk_offset += chunk_len
-		return total_data, sw
+        total_data = ''
+        chunk_offset = 0
+        while chunk_offset < length:
+            chunk_len = min(255, length-chunk_offset)
+            pdu = self.cla_byte + \
+                'b0%04x%02x' % (offset + chunk_offset, chunk_len)
+            try:
+                data, sw = self._tp.send_apdu_checksw(pdu)
+            except Exception as e:
+                raise ValueError('%s, failed to read (offset %d)' %
+                                 (str_sanitize(str(e)), offset))
+            total_data += data
+            chunk_offset += chunk_len
+        return total_data, sw
 
-	def update_binary(self, ef, data:str, offset:int=0, verify:bool=False, conserve:bool=False):
-		"""Execute UPDATE BINARY.
+    def update_binary(self, ef, data: str, offset: int = 0, verify: bool = False, conserve: bool = False):
+        """Execute UPDATE BINARY.
 
-		Args:
-			ef : string or list of strings indicating name or path of transparent EF
-			data : hex string of data to be written
-			offset : byte offset in file from which to start writing
-			verify : Whether or not to verify data after write
-		"""
-		data_length = len(data) // 2
+        Args:
+                ef : string or list of strings indicating name or path of transparent EF
+                data : hex string of data to be written
+                offset : byte offset in file from which to start writing
+                verify : Whether or not to verify data after write
+        """
+        data_length = len(data) // 2
 
-		# Save write cycles by reading+comparing before write
-		if conserve:
-			data_current, sw = self.read_binary(ef, data_length, offset)
-			if data_current == data:
-				return None, sw
+        # Save write cycles by reading+comparing before write
+        if conserve:
+            data_current, sw = self.read_binary(ef, data_length, offset)
+            if data_current == data:
+                return None, sw
 
-		self.select_path(ef)
-		total_data = ''
-		chunk_offset = 0
-		while chunk_offset < data_length:
-			chunk_len = min(255, data_length - chunk_offset)
-			# chunk_offset is bytes, but data slicing is hex chars, so we need to multiply by 2
-			pdu = self.cla_byte + 'd6%04x%02x' % (offset + chunk_offset, chunk_len) + data[chunk_offset*2 : (chunk_offset+chunk_len)*2]
-			try:
-				chunk_data, chunk_sw = self._tp.send_apdu_checksw(pdu)
-			except Exception as e:
-				raise ValueError('%s, failed to write chunk (chunk_offset %d, chunk_len %d)' % \
-						 (str_sanitize(str(e)), chunk_offset, chunk_len))
-			total_data += data
-			chunk_offset += chunk_len
-		if verify:
-			self.verify_binary(ef, data, offset)
-		return total_data, chunk_sw
+        self.select_path(ef)
+        total_data = ''
+        chunk_offset = 0
+        while chunk_offset < data_length:
+            chunk_len = min(255, data_length - chunk_offset)
+            # chunk_offset is bytes, but data slicing is hex chars, so we need to multiply by 2
+            pdu = self.cla_byte + \
+                'd6%04x%02x' % (offset + chunk_offset, chunk_len) + \
+                data[chunk_offset*2: (chunk_offset+chunk_len)*2]
+            try:
+                chunk_data, chunk_sw = self._tp.send_apdu_checksw(pdu)
+            except Exception as e:
+                raise ValueError('%s, failed to write chunk (chunk_offset %d, chunk_len %d)' %
+                                 (str_sanitize(str(e)), chunk_offset, chunk_len))
+            total_data += data
+            chunk_offset += chunk_len
+        if verify:
+            self.verify_binary(ef, data, offset)
+        return total_data, chunk_sw
 
-	def verify_binary(self, ef, data:str, offset:int=0):
-		"""Verify contents of transparent EF.
+    def verify_binary(self, ef, data: str, offset: int = 0):
+        """Verify contents of transparent EF.
 
-		Args:
-			ef : string or list of strings indicating name or path of transparent EF
-			data : hex string of expected data
-			offset : byte offset in file from which to start verifying
-		"""
-		res = self.read_binary(ef, len(data) // 2, offset)
-		if res[0].lower() != data.lower():
-			raise ValueError('Binary verification failed (expected %s, got %s)' % (data.lower(), res[0].lower()))
+        Args:
+                ef : string or list of strings indicating name or path of transparent EF
+                data : hex string of expected data
+                offset : byte offset in file from which to start verifying
+        """
+        res = self.read_binary(ef, len(data) // 2, offset)
+        if res[0].lower() != data.lower():
+            raise ValueError('Binary verification failed (expected %s, got %s)' % (
+                data.lower(), res[0].lower()))
 
-	def read_record(self, ef, rec_no:int):
-		"""Execute READ RECORD.
+    def read_record(self, ef, rec_no: int):
+        """Execute READ RECORD.
 
-		Args:
-			ef : string or list of strings indicating name or path of linear fixed EF
-			rec_no : record number to read
-		"""
-		r = self.select_path(ef)
-		rec_length = self.__record_len(r)
-		pdu = self.cla_byte + 'b2%02x04%02x' % (rec_no, rec_length)
-		return self._tp.send_apdu_checksw(pdu)
+        Args:
+                ef : string or list of strings indicating name or path of linear fixed EF
+                rec_no : record number to read
+        """
+        r = self.select_path(ef)
+        rec_length = self.__record_len(r)
+        pdu = self.cla_byte + 'b2%02x04%02x' % (rec_no, rec_length)
+        return self._tp.send_apdu_checksw(pdu)
 
-	def update_record(self, ef, rec_no:int, data:str, force_len:bool=False, verify:bool=False,
-					  conserve:bool=False):
-		"""Execute UPDATE RECORD.
+    def update_record(self, ef, rec_no: int, data: str, force_len: bool = False, verify: bool = False,
+                      conserve: bool = False):
+        """Execute UPDATE RECORD.
 
-		Args:
-			ef : string or list of strings indicating name or path of linear fixed EF
-			rec_no : record number to read
-			data : hex string of data to be written
-			force_len : enforce record length by using the actual data length
-			verify : verify data by re-reading the record
-			conserve : read record and compare it with data, skip write on match
-		"""
-		res = self.select_path(ef)
+        Args:
+                ef : string or list of strings indicating name or path of linear fixed EF
+                rec_no : record number to read
+                data : hex string of data to be written
+                force_len : enforce record length by using the actual data length
+                verify : verify data by re-reading the record
+                conserve : read record and compare it with data, skip write on match
+        """
+        res = self.select_path(ef)
 
-		if force_len:
-			# enforce the record length by the actual length of the given data input
-			rec_length = len(data) // 2
-		else:
-			# determine the record length from the select response of the file and pad
-			# the input data with 0xFF if necessary. In cases where the input data
-			# exceed we throw an exception.
-			rec_length = self.__record_len(res)
-			if (len(data) // 2 > rec_length):
-				raise ValueError('Data length exceeds record length (expected max %d, got %d)' % (rec_length, len(data) // 2))
-			elif (len(data) // 2 < rec_length):
-				data = rpad(data, rec_length * 2)
+        if force_len:
+            # enforce the record length by the actual length of the given data input
+            rec_length = len(data) // 2
+        else:
+            # determine the record length from the select response of the file and pad
+            # the input data with 0xFF if necessary. In cases where the input data
+            # exceed we throw an exception.
+            rec_length = self.__record_len(res)
+            if (len(data) // 2 > rec_length):
+                raise ValueError('Data length exceeds record length (expected max %d, got %d)' % (
+                    rec_length, len(data) // 2))
+            elif (len(data) // 2 < rec_length):
+                data = rpad(data, rec_length * 2)
 
-		# Save write cycles by reading+comparing before write
-		if conserve:
-			data_current, sw = self.read_record(ef, rec_no)
-			data_current = data_current[0:rec_length*2]
-			if data_current == data:
-				return None, sw
+        # Save write cycles by reading+comparing before write
+        if conserve:
+            data_current, sw = self.read_record(ef, rec_no)
+            data_current = data_current[0:rec_length*2]
+            if data_current == data:
+                return None, sw
 
-		pdu = (self.cla_byte + 'dc%02x04%02x' % (rec_no, rec_length)) + data
-		res = self._tp.send_apdu_checksw(pdu)
-		if verify:
-			self.verify_record(ef, rec_no, data)
-		return res
+        pdu = (self.cla_byte + 'dc%02x04%02x' % (rec_no, rec_length)) + data
+        res = self._tp.send_apdu_checksw(pdu)
+        if verify:
+            self.verify_record(ef, rec_no, data)
+        return res
 
-	def verify_record(self, ef, rec_no:int, data:str):
-		"""Verify record against given data
+    def verify_record(self, ef, rec_no: int, data: str):
+        """Verify record against given data
 
-		Args:
-			ef : string or list of strings indicating name or path of linear fixed EF
-			rec_no : record number to read
-			data : hex string of data to be verified
-		"""
-		res = self.read_record(ef, rec_no)
-		if res[0].lower() != data.lower():
-			raise ValueError('Record verification failed (expected %s, got %s)' % (data.lower(), res[0].lower()))
+        Args:
+                ef : string or list of strings indicating name or path of linear fixed EF
+                rec_no : record number to read
+                data : hex string of data to be verified
+        """
+        res = self.read_record(ef, rec_no)
+        if res[0].lower() != data.lower():
+            raise ValueError('Record verification failed (expected %s, got %s)' % (
+                data.lower(), res[0].lower()))
 
-	def record_size(self, ef):
-		"""Determine the record size of given file.
+    def record_size(self, ef):
+        """Determine the record size of given file.
 
-		Args:
-			ef : string or list of strings indicating name or path of linear fixed EF
-		"""
-		r = self.select_path(ef)
-		return self.__record_len(r)
+        Args:
+                ef : string or list of strings indicating name or path of linear fixed EF
+        """
+        r = self.select_path(ef)
+        return self.__record_len(r)
 
-	def record_count(self, ef):
-		"""Determine the number of records in given file.
+    def record_count(self, ef):
+        """Determine the number of records in given file.
 
-		Args:
-			ef : string or list of strings indicating name or path of linear fixed EF
-		"""
-		r = self.select_path(ef)
-		return self.__len(r) // self.__record_len(r)
+        Args:
+                ef : string or list of strings indicating name or path of linear fixed EF
+        """
+        r = self.select_path(ef)
+        return self.__len(r) // self.__record_len(r)
 
-	def binary_size(self, ef):
-		"""Determine the size of given transparent file.
+    def binary_size(self, ef):
+        """Determine the size of given transparent file.
+
+        Args:
+                ef : string or list of strings indicating name or path of transparent EF
+        """
+        r = self.select_path(ef)
+        return self.__len(r)
 
-		Args:
-			ef : string or list of strings indicating name or path of transparent EF
-		"""
-		r = self.select_path(ef)
-		return self.__len(r)
+    # TS 102 221 Section 11.3.1 low-level helper
+    def _retrieve_data(self, tag: int, first: bool = True):
+        if first:
+            pdu = '80cb008001%02x' % (tag)
+        else:
+            pdu = '80cb000000'
+        return self._tp.send_apdu_checksw(pdu)
 
-	# TS 102 221 Section 11.3.1 low-level helper
-	def _retrieve_data(self, tag:int, first:bool=True):
-		if first:
-			pdu = '80cb008001%02x' % (tag)
-		else:
-			pdu = '80cb000000'
-		return self._tp.send_apdu_checksw(pdu)
+    def retrieve_data(self, ef, tag: int):
+        """Execute RETRIEVE DATA, see also TS 102 221 Section 11.3.1.
 
-	def retrieve_data(self, ef, tag:int):
-		"""Execute RETRIEVE DATA, see also TS 102 221 Section 11.3.1.
+        Args
+                ef : string or list of strings indicating name or path of transparent EF
+                tag : BER-TLV Tag of value to be retrieved
+        """
+        r = self.select_path(ef)
+        if len(r[-1]) == 0:
+            return (None, None)
+        total_data = ''
+        # retrieve first block
+        data, sw = self._retrieve_data(tag, first=True)
+        total_data += data
+        while sw == '62f1' or sw == '62f2':
+            data, sw = self._retrieve_data(tag, first=False)
+            total_data += data
+        return total_data, sw
 
-		Args
-			ef : string or list of strings indicating name or path of transparent EF
-			tag : BER-TLV Tag of value to be retrieved
-		"""
-		r = self.select_path(ef)
-		if len(r[-1]) == 0:
-			return (None, None)
-		total_data = ''
-		# retrieve first block
-		data, sw = self._retrieve_data(tag, first=True)
-		total_data += data
-		while sw == '62f1' or sw == '62f2':
-			data, sw = self._retrieve_data(tag, first=False)
-			total_data += data
-		return total_data, sw
+    # TS 102 221 Section 11.3.2 low-level helper
+    def _set_data(self, data: str, first: bool = True):
+        if first:
+            p1 = 0x80
+        else:
+            p1 = 0x00
+        if isinstance(data, bytes) or isinstance(data, bytearray):
+            data = b2h(data)
+        pdu = '80db00%02x%02x%s' % (p1, len(data)//2, data)
+        return self._tp.send_apdu_checksw(pdu)
 
-	# TS 102 221 Section 11.3.2 low-level helper
-	def _set_data(self, data:str, first:bool=True):
-		if first:
-			p1 = 0x80
-		else:
-			p1 = 0x00
-		if isinstance(data, bytes) or isinstance(data, bytearray):
-			data = b2h(data)
-		pdu = '80db00%02x%02x%s' % (p1, len(data)//2, data)
-		return self._tp.send_apdu_checksw(pdu)
+    def set_data(self, ef, tag: int, value: str, verify: bool = False, conserve: bool = False):
+        """Execute SET DATA.
 
-	def set_data(self, ef, tag:int, value:str, verify:bool=False, conserve:bool=False):
-		"""Execute SET DATA.
+        Args
+                ef : string or list of strings indicating name or path of transparent EF
+                tag : BER-TLV Tag of value to be stored
+                value : BER-TLV value to be stored
+        """
+        r = self.select_path(ef)
+        if len(r[-1]) == 0:
+            return (None, None)
 
-		Args
-			ef : string or list of strings indicating name or path of transparent EF
-			tag : BER-TLV Tag of value to be stored
-			value : BER-TLV value to be stored
-		"""
-		r = self.select_path(ef)
-		if len(r[-1]) == 0:
-			return (None, None)
+        # in case of deleting the data, we only have 'tag' but no 'value'
+        if not value:
+            return self._set_data('%02x' % tag, first=True)
 
-		# in case of deleting the data, we only have 'tag' but no 'value'
-		if not value:
-			return self._set_data('%02x' % tag, first=True)
+        # FIXME: proper BER-TLV encode
+        tl = '%02x%s' % (tag, b2h(bertlv_encode_len(len(value)//2)))
+        tlv = tl + value
+        tlv_bin = h2b(tlv)
 
-		# FIXME: proper BER-TLV encode
-		tl = '%02x%s' % (tag, b2h(bertlv_encode_len(len(value)//2)))
-		tlv = tl + value
-		tlv_bin = h2b(tlv)
+        first = True
+        total_len = len(tlv_bin)
+        remaining = tlv_bin
+        while len(remaining) > 0:
+            fragment = remaining[:255]
+            rdata, sw = self._set_data(fragment, first=first)
+            first = False
+            remaining = remaining[255:]
+        return rdata, sw
 
-		first = True
-		total_len = len(tlv_bin)
-		remaining = tlv_bin
-		while len(remaining) > 0:
-			fragment = remaining[:255]
-			rdata, sw = self._set_data(fragment, first=first)
-			first = False
-			remaining = remaining[255:]
-		return rdata, sw
+    def run_gsm(self, rand: str):
+        """Execute RUN GSM ALGORITHM.
 
-	def run_gsm(self, rand:str):
-		"""Execute RUN GSM ALGORITHM.
+        Args:
+                rand : 16 byte random data as hex string (RAND)
+        """
+        if len(rand) != 32:
+            raise ValueError('Invalid rand')
+        self.select_path(['3f00', '7f20'])
+        return self._tp.send_apdu(self.cla_byte + '88000010' + rand)
 
-		Args:
-			rand : 16 byte random data as hex string (RAND)
-		"""
-		if len(rand) != 32:
-			raise ValueError('Invalid rand')
-		self.select_path(['3f00', '7f20'])
-		return self._tp.send_apdu(self.cla_byte + '88000010' + rand)
+    def authenticate(self, rand: str, autn: str, context='3g'):
+        """Execute AUTHENTICATE (USIM/ISIM).
 
-	def authenticate(self, rand:str, autn:str, context='3g'):
-		"""Execute AUTHENTICATE (USIM/ISIM).
+        Args:
+                rand : 16 byte random data as hex string (RAND)
+                autn : 8 byte Autentication Token (AUTN)
+                context : 16 byte random data ('3g' or 'gsm')
+        """
+        # 3GPP TS 31.102 Section 7.1.2.1
+        AuthCmd3G = Struct('rand'/LV, 'autn'/Optional(LV))
+        AuthResp3GSyncFail = Struct(Const(b'\xDC'), 'auts'/LV)
+        AuthResp3GSuccess = Struct(
+            Const(b'\xDB'), 'res'/LV, 'ck'/LV, 'ik'/LV, 'kc'/Optional(LV))
+        AuthResp3G = Select(AuthResp3GSyncFail, AuthResp3GSuccess)
+        # build parameters
+        cmd_data = {'rand': rand, 'autn': autn}
+        if context == '3g':
+            p2 = '81'
+        elif context == 'gsm':
+            p2 = '80'
+        (data, sw) = self._tp.send_apdu_constr_checksw(
+            self.cla_byte, '88', '00', p2, AuthCmd3G, cmd_data, AuthResp3G)
+        if 'auts' in data:
+            ret = {'synchronisation_failure': data}
+        else:
+            ret = {'successful_3g_authentication': data}
+        return (ret, sw)
 
-		Args:
-			rand : 16 byte random data as hex string (RAND)
-			autn : 8 byte Autentication Token (AUTN)
-			context : 16 byte random data ('3g' or 'gsm')
-		"""
-		# 3GPP TS 31.102 Section 7.1.2.1
-		AuthCmd3G = Struct('rand'/LV, 'autn'/Optional(LV))
-		AuthResp3GSyncFail = Struct(Const(b'\xDC'), 'auts'/LV)
-		AuthResp3GSuccess = Struct(Const(b'\xDB'), 'res'/LV, 'ck'/LV, 'ik'/LV, 'kc'/Optional(LV))
-		AuthResp3G = Select(AuthResp3GSyncFail, AuthResp3GSuccess)
-		# build parameters
-		cmd_data = {'rand': rand, 'autn': autn}
-		if context == '3g':
-			p2 = '81'
-		elif context == 'gsm':
-			p2 = '80'
-		(data, sw) = self._tp.send_apdu_constr_checksw(self.cla_byte, '88', '00', p2, AuthCmd3G, cmd_data, AuthResp3G)
-		if 'auts' in data:
-			ret = {'synchronisation_failure': data}
-		else:
-			ret = {'successful_3g_authentication': data}
-		return (ret, sw)
+    def status(self):
+        """Execute a STATUS command as per TS 102 221 Section 11.1.2."""
+        return self._tp.send_apdu_checksw('80F20000ff')
 
-	def status(self):
-		"""Execute a STATUS command as per TS 102 221 Section 11.1.2."""
-		return self._tp.send_apdu_checksw('80F20000ff')
+    def deactivate_file(self):
+        """Execute DECATIVATE FILE command as per TS 102 221 Section 11.1.14."""
+        return self._tp.send_apdu_constr_checksw(self.cla_byte, '04', '00', '00', None, None, None)
 
-	def deactivate_file(self):
-		"""Execute DECATIVATE FILE command as per TS 102 221 Section 11.1.14."""
-		return self._tp.send_apdu_constr_checksw(self.cla_byte, '04', '00', '00', None, None, None)
+    def activate_file(self, fid):
+        """Execute ACTIVATE FILE command as per TS 102 221 Section 11.1.15.
 
-	def activate_file(self, fid):
-		"""Execute ACTIVATE FILE command as per TS 102 221 Section 11.1.15.
+        Args:
+                fid : file identifier as hex string
+        """
+        return self._tp.send_apdu_checksw(self.cla_byte + '44000002' + fid)
 
-		Args:
-			fid : file identifier as hex string
-		"""
-		return self._tp.send_apdu_checksw(self.cla_byte + '44000002' + fid)
+    def manage_channel(self, mode='open', lchan_nr=0):
+        """Execute MANAGE CHANNEL command as per TS 102 221 Section 11.1.17.
 
-	def manage_channel(self, mode='open', lchan_nr=0):
-		"""Execute MANAGE CHANNEL command as per TS 102 221 Section 11.1.17.
+        Args:
+                mode : logical channel operation code ('open' or 'close')
+                lchan_nr : logical channel number (1-19, 0=assigned by UICC)
+        """
+        if mode == 'close':
+            p1 = 0x80
+        else:
+            p1 = 0x00
+        pdu = self.cla_byte + '70%02x%02x00' % (p1, lchan_nr)
+        return self._tp.send_apdu_checksw(pdu)
 
-		Args:
-			mode : logical channel operation code ('open' or 'close')
-			lchan_nr : logical channel number (1-19, 0=assigned by UICC)
-		"""
-		if mode == 'close':
-			p1 = 0x80
-		else:
-			p1 = 0x00
-		pdu = self.cla_byte + '70%02x%02x00' % (p1, lchan_nr)
-		return self._tp.send_apdu_checksw(pdu)
+    def reset_card(self):
+        """Physically reset the card"""
+        return self._tp.reset_card()
 
-	def reset_card(self):
-		"""Physically reset the card"""
-		return self._tp.reset_card()
+    def _chv_process_sw(self, op_name, chv_no, pin_code, sw):
+        if sw_match(sw, '63cx'):
+            raise RuntimeError('Failed to %s chv_no 0x%02X with code 0x%s, %i tries left.' %
+                               (op_name, chv_no, b2h(pin_code).upper(), int(sw[3])))
+        elif (sw != '9000'):
+            raise SwMatchError(sw, '9000')
 
-	def _chv_process_sw(self, op_name, chv_no, pin_code, sw):
-		if sw_match(sw, '63cx'):
-			raise RuntimeError('Failed to %s chv_no 0x%02X with code 0x%s, %i tries left.' %
-							   (op_name, chv_no, b2h(pin_code).upper(), int(sw[3])))
-		elif (sw != '9000'):
-			raise SwMatchError(sw, '9000')
+    def verify_chv(self, chv_no: int, code: str):
+        """Verify a given CHV (Card Holder Verification == PIN)
 
-	def verify_chv(self, chv_no:int, code:str):
-		"""Verify a given CHV (Card Holder Verification == PIN)
+        Args:
+                chv_no : chv number (1=CHV1, 2=CHV2, ...)
+                code : chv code as hex string
+        """
+        fc = rpad(b2h(code), 16)
+        data, sw = self._tp.send_apdu(
+            self.cla_byte + '2000' + ('%02X' % chv_no) + '08' + fc)
+        self._chv_process_sw('verify', chv_no, code, sw)
+        return (data, sw)
 
-		Args:
-			chv_no : chv number (1=CHV1, 2=CHV2, ...)
-			code : chv code as hex string
-		"""
-		fc = rpad(b2h(code), 16)
-		data, sw = self._tp.send_apdu(self.cla_byte + '2000' + ('%02X' % chv_no) + '08' + fc)
-		self._chv_process_sw('verify', chv_no, code, sw)
-		return (data, sw)
+    def unblock_chv(self, chv_no: int, puk_code: str, pin_code: str):
+        """Unblock a given CHV (Card Holder Verification == PIN)
 
-	def unblock_chv(self, chv_no:int, puk_code:str, pin_code:str):
-		"""Unblock a given CHV (Card Holder Verification == PIN)
+        Args:
+                chv_no : chv number (1=CHV1, 2=CHV2, ...)
+                puk_code : puk code as hex string
+                pin_code : new chv code as hex string
+        """
+        fc = rpad(b2h(puk_code), 16) + rpad(b2h(pin_code), 16)
+        data, sw = self._tp.send_apdu(
+            self.cla_byte + '2C00' + ('%02X' % chv_no) + '10' + fc)
+        self._chv_process_sw('unblock', chv_no, pin_code, sw)
+        return (data, sw)
 
-		Args:
-			chv_no : chv number (1=CHV1, 2=CHV2, ...)
-			puk_code : puk code as hex string
-			pin_code : new chv code as hex string
-		"""
-		fc = rpad(b2h(puk_code), 16) + rpad(b2h(pin_code), 16)
-		data, sw = self._tp.send_apdu(self.cla_byte + '2C00' + ('%02X' % chv_no) + '10' + fc)
-		self._chv_process_sw('unblock', chv_no, pin_code, sw)
-		return (data, sw)
+    def change_chv(self, chv_no: int, pin_code: str, new_pin_code: str):
+        """Change a given CHV (Card Holder Verification == PIN)
 
-	def change_chv(self, chv_no:int, pin_code:str, new_pin_code:str):
-		"""Change a given CHV (Card Holder Verification == PIN)
+        Args:
+                chv_no : chv number (1=CHV1, 2=CHV2, ...)
+                pin_code : current chv code as hex string
+                new_pin_code : new chv code as hex string
+        """
+        fc = rpad(b2h(pin_code), 16) + rpad(b2h(new_pin_code), 16)
+        data, sw = self._tp.send_apdu(
+            self.cla_byte + '2400' + ('%02X' % chv_no) + '10' + fc)
+        self._chv_process_sw('change', chv_no, pin_code, sw)
+        return (data, sw)
 
-		Args:
-			chv_no : chv number (1=CHV1, 2=CHV2, ...)
-			pin_code : current chv code as hex string
-			new_pin_code : new chv code as hex string
-		"""
-		fc = rpad(b2h(pin_code), 16) + rpad(b2h(new_pin_code), 16)
-		data, sw = self._tp.send_apdu(self.cla_byte + '2400' + ('%02X' % chv_no) + '10' + fc)
-		self._chv_process_sw('change', chv_no, pin_code, sw)
-		return (data, sw)
+    def disable_chv(self, chv_no: int, pin_code: str):
+        """Disable a given CHV (Card Holder Verification == PIN)
 
-	def disable_chv(self, chv_no:int, pin_code:str):
-		"""Disable a given CHV (Card Holder Verification == PIN)
+        Args:
+                chv_no : chv number (1=CHV1, 2=CHV2, ...)
+                pin_code : current chv code as hex string
+                new_pin_code : new chv code as hex string
+        """
+        fc = rpad(b2h(pin_code), 16)
+        data, sw = self._tp.send_apdu(
+            self.cla_byte + '2600' + ('%02X' % chv_no) + '08' + fc)
+        self._chv_process_sw('disable', chv_no, pin_code, sw)
+        return (data, sw)
 
-		Args:
-			chv_no : chv number (1=CHV1, 2=CHV2, ...)
-			pin_code : current chv code as hex string
-			new_pin_code : new chv code as hex string
-		"""
-		fc = rpad(b2h(pin_code), 16)
-		data, sw = self._tp.send_apdu(self.cla_byte + '2600' + ('%02X' % chv_no) + '08' + fc)
-		self._chv_process_sw('disable', chv_no, pin_code, sw)
-		return (data, sw)
+    def enable_chv(self, chv_no: int, pin_code: str):
+        """Enable a given CHV (Card Holder Verification == PIN)
 
-	def enable_chv(self, chv_no:int, pin_code:str):
-		"""Enable a given CHV (Card Holder Verification == PIN)
+        Args:
+                chv_no : chv number (1=CHV1, 2=CHV2, ...)
+                pin_code : chv code as hex string
+        """
+        fc = rpad(b2h(pin_code), 16)
+        data, sw = self._tp.send_apdu(
+            self.cla_byte + '2800' + ('%02X' % chv_no) + '08' + fc)
+        self._chv_process_sw('enable', chv_no, pin_code, sw)
+        return (data, sw)
 
-		Args:
-			chv_no : chv number (1=CHV1, 2=CHV2, ...)
-			pin_code : chv code as hex string
-		"""
-		fc = rpad(b2h(pin_code), 16)
-		data, sw = self._tp.send_apdu(self.cla_byte + '2800' + ('%02X' % chv_no) + '08' + fc)
-		self._chv_process_sw('enable', chv_no, pin_code, sw)
-		return (data, sw)
+    def envelope(self, payload: str):
+        """Send one ENVELOPE command to the SIM
 
-	def envelope(self, payload:str):
-		"""Send one ENVELOPE command to the SIM
+        Args:
+                payload : payload as hex string
+        """
+        return self._tp.send_apdu_checksw('80c20000%02x%s' % (len(payload)//2, payload))
 
-		Args:
-			payload : payload as hex string
-		"""
-		return self._tp.send_apdu_checksw('80c20000%02x%s' % (len(payload)//2, payload))
+    def terminal_profile(self, payload: str):
+        """Send TERMINAL PROFILE to card
 
-	def terminal_profile(self, payload:str):
-		"""Send TERMINAL PROFILE to card
+        Args:
+                payload : payload as hex string
+        """
+        data_length = len(payload) // 2
+        data, sw = self._tp.send_apdu(('80100000%02x' % data_length) + payload)
+        return (data, sw)
 
-		Args:
-			payload : payload as hex string
-		"""
-		data_length = len(payload) // 2
-		data, sw = self._tp.send_apdu(('80100000%02x' % data_length) + payload)
-		return (data, sw)
+    # ETSI TS 102 221 11.1.22
+    def suspend_uicc(self, min_len_secs: int = 60, max_len_secs: int = 43200):
+        """Send SUSPEND UICC to the card.
 
-	# ETSI TS 102 221 11.1.22
-	def suspend_uicc(self, min_len_secs:int=60, max_len_secs:int=43200):
-		"""Send SUSPEND UICC to the card.
+        Args:
+                 min_len_secs : mimumum suspend time seconds
+                 max_len_secs : maximum suspend time seconds
+        """
+        def encode_duration(secs: int) -> Hexstr:
+            if secs >= 10*24*60*60:
+                return '04%02x' % (secs // (10*24*60*60))
+            elif secs >= 24*60*60:
+                return '03%02x' % (secs // (24*60*60))
+            elif secs >= 60*60:
+                return '02%02x' % (secs // (60*60))
+            elif secs >= 60:
+                return '01%02x' % (secs // 60)
+            else:
+                return '00%02x' % secs
 
-		Args:
-			 min_len_secs : mimumum suspend time seconds
-			 max_len_secs : maximum suspend time seconds
-		"""
-		def encode_duration(secs:int) -> Hexstr:
-			if secs >= 10*24*60*60:
-				return '04%02x' % (secs // (10*24*60*60))
-			elif secs >= 24*60*60:
-				return '03%02x' % (secs // (24*60*60))
-			elif secs >= 60*60:
-				return '02%02x' % (secs // (60*60))
-			elif secs >= 60:
-				return '01%02x' % (secs // 60)
-			else:
-				return '00%02x' % secs
-		def decode_duration(enc:Hexstr) -> int:
-			time_unit = enc[:2]
-			length = h2i(enc[2:4])
-			if time_unit == '04':
-				return length * 10*24*60*60
-			elif time_unit == '03':
-				return length * 24*60*60
-			elif time_unit == '02':
-				return length * 60*60
-			elif time_unit == '01':
-				return length * 60
-			elif time_unit == '00':
-				return length
-			else:
-				raise ValueError('Time unit must be 0x00..0x04')
-		min_dur_enc = encode_duration(min_len_secs)
-		max_dur_enc = encode_duration(max_len_secs)
-		data, sw = self._tp.send_apdu_checksw('8076000004' + min_dur_enc + max_dur_enc)
-		negotiated_duration_secs = decode_duration(data[:4])
-		resume_token = data[4:]
-		return (negotiated_duration_secs, resume_token, sw)
+        def decode_duration(enc: Hexstr) -> int:
+            time_unit = enc[:2]
+            length = h2i(enc[2:4])
+            if time_unit == '04':
+                return length * 10*24*60*60
+            elif time_unit == '03':
+                return length * 24*60*60
+            elif time_unit == '02':
+                return length * 60*60
+            elif time_unit == '01':
+                return length * 60
+            elif time_unit == '00':
+                return length
+            else:
+                raise ValueError('Time unit must be 0x00..0x04')
+        min_dur_enc = encode_duration(min_len_secs)
+        max_dur_enc = encode_duration(max_len_secs)
+        data, sw = self._tp.send_apdu_checksw(
+            '8076000004' + min_dur_enc + max_dur_enc)
+        negotiated_duration_secs = decode_duration(data[:4])
+        resume_token = data[4:]
+        return (negotiated_duration_secs, resume_token, sw)