code: def _get_association_classes(self, namespace):
          
  
          class_repo = self._get_class_repo(namespace)
          # associator_classes = []
          for cl in six.itervalues(class_repo):
              if 'Association' in cl.qualifiers:
                  yield cl
          return
docs: Return iterator of associator classes from the class repo
  
          Returns the classes that have associations qualifier.
          Does NOT copy so these are what is in repository. User functions
          MUST NOT modify these classes.
  
          Returns: Returns generator where each yield returns a single
                   association class