class_docstr: Simple GRUModel for testing.
  
  Args:
      output_dim (int): Dimension of the network output.
      hidden_dim (int): Hidden dimension for GRU cell.
      name (str): Model name, also the variable scope.
      args (list): Unused positionl arguments.
      kwargs (dict): Unused keyword arguments.
docstr: Network input spec.
  
  Return:
      list[str]: List of key(str) for the network outputs.
docstr_tok: ["Network","input","spec",".","Return",":","list","[","str","]",":","List","of","key","(","str",")","for","the","network","outputs","."]
code: def network_input_spec(self):
      """Network input spec.
  
      Return:
          list[str]: List of key(str) for the network outputs.
  
      """
      return ["full_input", "step_input", "step_hidden_input"]
  
imports: import tensorflow
  from garage.tf.models import Model
label_desc: Use image node_id 2 for calling the SimpleGRUModel obj's underlying member method code with example usage: obj.network_input_spec() and returns: list