code: def to_deeper_graph(graph):
      ''' deeper graph
      '''
  
      weighted_layer_ids = graph.deep_layer_ids()
      if len(weighted_layer_ids) >= Constant.MAX_LAYERS:
          return None
  
      deeper_layer_ids = sample(weighted_layer_ids, 1)
  
      for layer_id in deeper_layer_ids:
          layer = graph.layer_list[layer_id]
          new_layer = create_new_layer(layer, graph.n_dim)
          graph.to_deeper_model(layer_id, new_layer)
      return grapf to_deeper_graph(graph):
      ''' deeper graph
      '''
  
      weighted_layer_ids = graph.deep_layer_ids()
      if len(weighted_layer_ids) >= Constant.MAX_LAYERS:
          return None
  
      deeper_layer_ids = sample(weighted_layer_ids, 1)
  
      for layer_id in deeper_layer_ids:
          layer = graph.layer_list[layer_id]
          new_layer = create_new_layer(layer, graph.n_dim)
          graph.to_deeper_model(layer_id, new_layer)
      return graph
docs: deeper graph