code: def __call__(self, compose_fn):
      # TODO(fengliuai): more sanity check of the input function and make sure
      # the bounded arguments of the function matches the 'inputs' and 'attrs'.
      setattr(compose_fn, "_tfr_op_name", self._op_name)
      return compose_fn
  
label_desc: Use image node_id 2 for calling the Composite obj's underlying member method code with example usage: obj.__call__(compose_fn) and returns: compose_fn