code: def get_activities_by_query(self, activity_query=None):
          
          url_path = construct_url('activities',
                                   bank_id=self._catalog_idstr)
          query_terms = [v for k, v in activity_query._query_terms.items()]
          url_path += '?' + '&'.join(query_terms)
          objects.ActivityList(self._get_request(url_path))
docs: Gets a list of Activities matching the given activity query.
  
          arg:    activityQuery (osid.learning.ActivityQuery): the
                  activity query
          return: (osid.learning.ActivityList) - the returned ActivityList
          raise:  NullArgument - activityQuery is null
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure
          raise:  Unsupported - activityQuery is not of this service
          compliance: mandatory - This method must be implemented.