Fix parsing error

asn1_value_editor/vdm_vn.py

@@ -167,7 +167,8 @@ def vdm_to_swig(vdm, dest, sort, ASN1Swig, ASN1_AST, var=None):
             none - "dest" is modified by this function
     '''
     # Parse the VDM string and transform it to a python value
-    var = var or value.parseString(vdm, True)[0]
+    if var is None:
+        var = value.parseString(vdm, True)[0]
 
     def find_basic_type(a_type):
         ''' Return the ASN.1 basic type of a_type '''

asn1_value_editor/vn.py

@@ -212,7 +212,8 @@ def valueNotationToSwig(gser, dest, sort, ASN1Swig, ASN1_AST, var=None):
         Outputs:
             none - "dest" is modified by this function
     '''
-    var = var or value.parseString(gser, True)[0]
+    if var is None:
+        var = value.parseString(gser, True)[0]
     def reach(field, orig, idx=True):
         ''' Helper: move swig pointer to the next field, and optionaly
             index (if idx=True)