code: def __call__(self, graph):
      value = np.zeros((graph.n_nodes, 1)) + self.value
      if graph.x is None:
          graph.x = value
      else:
          graph.x = np.concatenate((graph.x, value), axis=-1)
  
      return graph
  
imports: import numpy
label_desc: Use image node_id 2 for calling the Constant obj's underlying member method code with example usage: obj.__call__(graph) and returns: graph