diff --git a/pySim/card_handler.py b/pySim/card_handler.py
index 0425e33..57e0d32 100644
--- a/pySim/card_handler.py
+++ b/pySim/card_handler.py
@@ -30,116 +30,118 @@
 import sys
 import yaml
 
+
 class CardHandlerBase:
-	"""Abstract base class representing a mechanism for card insertion/removal."""
+    """Abstract base class representing a mechanism for card insertion/removal."""
 
-	def __init__(self, sl:LinkBase):
-		self.sl = sl
+    def __init__(self, sl: LinkBase):
+        self.sl = sl
 
-	def get(self, first:bool = False):
-		"""Method called when pySim needs a new card to be inserted.
+    def get(self, first: bool = False):
+        """Method called when pySim needs a new card to be inserted.
 
-		Args:
-			first : set to true when the get method is called the
-				first time. This is required to prevent blocking
-				when a card is already inserted into the reader.
-				The reader API would not recognize that card as
-				"new card" until it would be removed and re-inserted
-				again.
-		"""
-		print("Ready for Programming: ", end='')
-		self._get(first)
+        Args:
+                first : set to true when the get method is called the
+                        first time. This is required to prevent blocking
+                        when a card is already inserted into the reader.
+                        The reader API would not recognize that card as
+                        "new card" until it would be removed and re-inserted
+                        again.
+        """
+        print("Ready for Programming: ", end='')
+        self._get(first)
 
-	def error(self):
-		"""Method called when pySim failed to program a card. Move card to 'bad' batch."""
-		print("Programming failed: ", end='')
-		self._error()
+    def error(self):
+        """Method called when pySim failed to program a card. Move card to 'bad' batch."""
+        print("Programming failed: ", end='')
+        self._error()
 
-	def done(self):
-		"""Method called when pySim failed to program a card. Move card to 'good' batch."""
-		print("Programming successful: ", end='')
-		self._done()
+    def done(self):
+        """Method called when pySim failed to program a card. Move card to 'good' batch."""
+        print("Programming successful: ", end='')
+        self._done()
 
-	def _get(self, first:bool = False):
-		pass
+    def _get(self, first: bool = False):
+        pass
 
-	def _error(self):
-		pass
+    def _error(self):
+        pass
 
-	def _done(self):
-		pass
+    def _done(self):
+        pass
 
 
 class CardHandler(CardHandlerBase):
-	"""Manual card handler: User is prompted to insert/remove card from the reader."""
+    """Manual card handler: User is prompted to insert/remove card from the reader."""
 
-	def _get(self, first:bool = False):
-		print("Insert card now (or CTRL-C to cancel)")
-		self.sl.wait_for_card(newcardonly=not first)
+    def _get(self, first: bool = False):
+        print("Insert card now (or CTRL-C to cancel)")
+        self.sl.wait_for_card(newcardonly=not first)
 
-	def _error(self):
-		print("Remove card from reader")
-		print("")
+    def _error(self):
+        print("Remove card from reader")
+        print("")
 
-	def _done(self):
-		print("Remove card from reader")
-		print("")
+    def _done(self):
+        print("Remove card from reader")
+        print("")
 
 
 class CardHandlerAuto(CardHandlerBase):
-	"""Automatic card handler: A machine is used to handle the cards."""
+    """Automatic card handler: A machine is used to handle the cards."""
 
-	verbose = True
+    verbose = True
 
-	def __init__(self, sl:LinkBase, config_file:str):
-		super().__init__(sl)
-		print("Card handler Config-file: " + str(config_file))
-		with open(config_file) as cfg:
-			self.cmds = yaml.load(cfg, Loader=yaml.FullLoader)
-		self.verbose = (self.cmds.get('verbose') == True)
+    def __init__(self, sl: LinkBase, config_file: str):
+        super().__init__(sl)
+        print("Card handler Config-file: " + str(config_file))
+        with open(config_file) as cfg:
+            self.cmds = yaml.load(cfg, Loader=yaml.FullLoader)
+        self.verbose = (self.cmds.get('verbose') == True)
 
-	def __print_outout(self, out):
-		print("")
-		print("Card handler output:")
-		print("---------------------8<---------------------")
-		stdout = out[0].strip()
-		if len(stdout) > 0:
-			print("stdout:")
-			print(stdout)
-		stderr = out[1].strip()
-		if len(stderr) > 0:
-			print("stderr:")
-			print(stderr)
-		print("---------------------8<---------------------")
-		print("")
+    def __print_outout(self, out):
+        print("")
+        print("Card handler output:")
+        print("---------------------8<---------------------")
+        stdout = out[0].strip()
+        if len(stdout) > 0:
+            print("stdout:")
+            print(stdout)
+        stderr = out[1].strip()
+        if len(stderr) > 0:
+            print("stderr:")
+            print(stderr)
+        print("---------------------8<---------------------")
+        print("")
 
-	def __exec_cmd(self, command):
-		print("Card handler Commandline: " + str(command))
+    def __exec_cmd(self, command):
+        print("Card handler Commandline: " + str(command))
 
-		proc = subprocess.Popen([command], stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
-		out = proc.communicate()
-		rc = proc.returncode
+        proc = subprocess.Popen(
+            [command], stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
+        out = proc.communicate()
+        rc = proc.returncode
 
-		if rc != 0 or self.verbose:
-			self.__print_outout(out)
+        if rc != 0 or self.verbose:
+            self.__print_outout(out)
 
-		if rc != 0:
-			print("")
-			print("Error: Card handler failure! (rc=" + str(rc) + ")")
-			sys.exit(rc)
+        if rc != 0:
+            print("")
+            print("Error: Card handler failure! (rc=" + str(rc) + ")")
+            sys.exit(rc)
 
-	def _get(self, first:bool = False):
-		print("Transporting card into the reader-bay...")
-		self.__exec_cmd(self.cmds['get'])
-		if self.sl:
-			self.sl.connect()
+    def _get(self, first: bool = False):
+        print("Transporting card into the reader-bay...")
+        self.__exec_cmd(self.cmds['get'])
+        if self.sl:
+            self.sl.connect()
 
-	def _error(self):
-		print("Transporting card to the error-bin...")
-		self.__exec_cmd(self.cmds['error'])
-		print("")
+    def _error(self):
+        print("Transporting card to the error-bin...")
+        self.__exec_cmd(self.cmds['error'])
+        print("")
 
-	def _done(self):
-		print("Transporting card into the collector bin...")
-		self.__exec_cmd(self.cmds['done'])
-		print("")
+    def _done(self):
+        print("Transporting card into the collector bin...")
+        self.__exec_cmd(self.cmds['done'])
+        print("")