else:
        return None

    func = ns[f_name]

    op_def, derived_attrs = self._op_defs.lookup(f_name, func)
    if op_def is None:
      return None
    pos = tf_inspect.getfullargspec(func).args.index(str(name))

    if pos < len(op_def.input_arg):
      arg_def = op_def.input_arg[pos]
      return {_get_type_from_proto(arg_def)}