filesystem: Fix TLV decode/encode

We cannot call a method of a class without instantiating it

Change-Id: I6d7c1bf49a8eaf3d8e50fb12888bf3d5b46b6c55
diff --git a/pySim/filesystem.py b/pySim/filesystem.py
index 3e9d52e..7100b21 100644
--- a/pySim/filesystem.py
+++ b/pySim/filesystem.py
@@ -532,8 +532,9 @@
         if self._construct:
             return parse_construct(self._construct, raw_bin_data)
         elif self._tlv:
-            self._tlv.from_tlv(raw_bin_data)
-            return self._tlv.to_dict()
+            t = self._tlv()
+            t.from_tlv(raw_bin_data)
+            return t.to_dict()
         return {'raw': raw_bin_data.hex()}
 
     def decode_hex(self, raw_hex_data:str) -> dict:
@@ -558,8 +559,9 @@
         if self._construct:
             return parse_construct(self._construct, raw_bin_data)
         elif self._tlv:
-            self._tlv.from_tlv(raw_bin_data)
-            return self._tlv.to_dict()
+            t = self._tlv()
+            t.from_tlv(raw_bin_data)
+            return t.to_dict()
         return {'raw': raw_bin_data.hex()}
 
     def encode_bin(self, abstract_data:dict) -> bytearray:
@@ -583,8 +585,9 @@
         if self._construct:
             return self._construct.build(abstract_data)
         elif self._tlv:
-            self._tlv.from_dict(abstract_data)
-            return self._tlv.to_tlv()
+            t = self._tlv()
+            t.from_dict(abstract_data)
+            return t.to_tlv()
         raise NotImplementedError("%s encoder not yet implemented. Patches welcome." % self)
 
     def encode_hex(self, abstract_data:dict) -> str:
@@ -609,8 +612,9 @@
         if self._construct:
             return b2h(self._construct.build(abstract_data))
         elif self._tlv:
-            self._tlv.from_dict(abstract_data)
-            return b2h(self._tlv.to_tlv())
+            t = self._tlv()
+            t.from_dict(abstract_data)
+            return b2h(t.to_tlv())
         raise NotImplementedError("%s encoder not yet implemented. Patches welcome." % self)
 
 
@@ -767,8 +771,9 @@
         if self._construct:
             return parse_construct(self._construct, raw_bin_data)
         elif self._tlv:
-            self._tlv.from_tlv(raw_bin_data)
-            return self._tlv.to_dict()
+            t = self._tlv()
+            t.from_tlv(raw_bin_data)
+            return t.to_dict()
         return {'raw': raw_bin_data.hex()}
 
     def decode_record_bin(self, raw_bin_data:bytearray) -> dict:
@@ -793,8 +798,9 @@
         if self._construct:
             return parse_construct(self._construct, raw_bin_data)
         elif self._tlv:
-            self._tlv.from_tlv(raw_bin_data)
-            return self._tlv.to_dict()
+            t = self._tlv()
+            t.from_tlv(raw_bin_data)
+            return t.to_dict()
         return {'raw': raw_hex_data}
 
     def encode_record_hex(self, abstract_data:dict) -> str:
@@ -819,8 +825,9 @@
         if self._construct:
             return b2h(self._construct.build(abstract_data))
         elif self._tlv:
-            self._tlv.from_dict(abstract_data)
-            return b2h(self._tlv.to_tlv())
+            t = self._tlv()
+            t.from_dict(abstract_data)
+            return b2h(t.to_tlv())
         raise NotImplementedError("%s encoder not yet implemented. Patches welcome." % self)
 
     def encode_record_bin(self, abstract_data:dict) -> bytearray:
@@ -844,8 +851,9 @@
         if self._construct:
             return self._construct.build(abstract_data)
         elif self._tlv:
-            self._tlv.from_dict(abstract_data)
-            return self._tlv.to_tlv()
+            t = self._tlv()
+            t.from_dict(abstract_data)
+            return t.to_tlv()
         raise NotImplementedError("%s encoder not yet implemented. Patches welcome." % self)
 
 class CyclicEF(LinFixedEF):
@@ -901,8 +909,9 @@
         if self._construct:
             return parse_construct(self._construct, raw_bin_data)
         elif self._tlv:
-            self._tlv.from_tlv(raw_bin_data)
-            return self._tlv.to_dict()
+            t = self._tlv()
+            t.from_tlv(raw_bin_data)
+            return t.to_dict()
         return {'raw': raw_hex_data}
 
     def decode_record_bin(self, raw_bin_data:bytearray) -> dict:
@@ -927,8 +936,9 @@
         if self._construct:
             return parse_construct(self._construct, raw_bin_data)
         elif self._tlv:
-            self._tlv.from_tlv(raw_bin_data)
-            return self._tlv.to_dict()
+            t = self._tlv()
+            t.from_tlv(raw_bin_data)
+            return t.to_dict()
         return {'raw': raw_hex_data}
 
     def encode_record_hex(self, abstract_data:dict) -> str:
@@ -952,8 +962,9 @@
         if self._construct:
             return b2h(filter_dict(self._construct.build(abstract_data)))
         elif self._tlv:
-            self._tlv.from_dict(abstract_data)
-            return b2h(self._tlv.to_tlv())
+            t = self._tlv()
+            t.from_dict(abstract_data)
+            return b2h(t.to_tlv())
         raise NotImplementedError("%s encoder not yet implemented. Patches welcome." % self)
 
     def encode_record_bin(self, abstract_data:dict) -> bytearray:
@@ -977,8 +988,9 @@
         if self._construct:
             return filter_dict(self._construct.build(abstract_data))
         elif self._tlv:
-            self._tlv.from_dict(abstract_data)
-            return self._tlv.to_tlv()
+            t = self._tlv()
+            t.from_dict(abstract_data)
+            return t.to_tlv()
         raise NotImplementedError("%s encoder not yet implemented. Patches welcome." % self)
 
     def _decode_bin(self, raw_bin_data:bytearray):