we should also correctly handle Python 3.5 **kwargs in class definitions

astor/codegen.py

@@ -212,7 +212,10 @@ class SourceGenerator(ExplicitNodeVisitor):
         #      with python 2.6.
         if hasattr(node, 'keywords'):
             for keyword in node.keywords:
-                self.write(paren_or_comma, keyword.arg, '=', keyword.value)
+                if keyword.arg is None:
+                    self.write(paren_or_comma, '**', keyword.value)
+                else:
+                    self.write(paren_or_comma, keyword.arg, '=', keyword.value)
             if sys.version_info < (3, 5):
                 self.conditional_write(paren_or_comma, '*', node.starargs)
                 self.conditional_write(paren_or_comma, '**', node.kwargs)

tests/test_codegen.py

@@ -102,6 +102,12 @@ class CodegenTestCase(unittest.TestCase):
                     return datum""")
         self.assertAstSourceEqualIfAtLeastVersion(source, (3, 5))
 
+    def test_class_definition_with_starbases_and_kwargs(self):
+        source = textwrap.dedent("""\
+        class TreeFactory(*[FactoryMixin, TreeBase], **{'metaclass': Foo}):
+            pass""")
+        self.assertAstSourceEqualIfAtLeastVersion(source, (3, 0))
+
 
 if __name__ == '__main__':
     unittest.main()