code: def get_meta_graph(self, tags=None):
      
      matches = [meta_graph
                 for meta_graph in self.meta_graphs
                 if set(meta_graph.meta_info_def.tags) == set(tags or [])]
      if not matches:
        raise KeyError("SavedModelHandler has no graph with tags: %r" % tags)
      if len(matches) != 1:
        raise KeyError(
            "SavedModelHandler has multiple graphs with tags %r" % tags)
      return matches[0]
docs: Returns the matching MetaGraphDef or raises KeyError.