fix: ignore flake false positives about undefined names

NOTE: MorphologyImportError is undefined and should be fixed.

neuroml/loaders.py

@@ -114,7 +114,8 @@ def load_swc_single(cls,  src, name=None):
         if len(id_to_index_dict) != len(index_to_id):
             s =  "Internal Error Loading SWC: Index and ID map are different lengths."
             s += " [ID:%d, Index:%d]"%( len(index_to_id), len(id_to_index_dict) )
-            raise MorphologyImportError(s)
+            # TODO: this is undefined!!
+            raise MorphologyImportError(s)  # noqa: F821
 
         # Vertices and section types are easy:
         vertices =  d[ ['x','y','z','r'] ]

neuroml/nml/nml.py

@@ -35,7 +35,7 @@
 
 Validate_simpletypes_ = True
 if sys.version_info.major == 2:
-    BaseStrType_ = basestring
+    BaseStrType_ = basestring  # noqa: F821
 else:
     BaseStrType_ = str
 
@@ -415,7 +415,7 @@ def gds_encode(instring):
         def convert_unicode(instring):
             if isinstance(instring, str):
                 result = quote_xml(instring)
-            elif sys.version_info.major == 2 and isinstance(instring, unicode):
+            elif sys.version_info.major == 2 and isinstance(instring, unicode): # noqa: F821
                 result = quote_xml(instring).encode('utf8')
             else:
                 result = GeneratedsSuper.gds_encode(str(instring))