pySim/tlv.py: Don't create an exception from within raise

An invalid variable used in a raise ValueError() would cause a further
exception, depriving the user of a meaningful error message.

Change-Id: I6eb31b91bd69c311f07ff259a424edc58b57529a

pySim/tlv.py

@@ -395,7 +395,7 @@ class TLV_IE_Collection(metaclass=TlvCollectionMeta):
                     res.append(inst)
                 else:
                     raise ValueError('%s: Unknown TLV Class %s in %s; expected %s' %
-                                     (self, i[0], decoded, self.members_by_name.keys()))
+                                     (self, k, decoded, self.members_by_name.keys()))
         self.children = res
         return res