code: def test_callable(self):
      class Foo(object):
          def __call__(self, a, b):
              return a + b
  
      self.assertEqual(("a", "b"), function_utils.fn_args(Foo()))
  
imports: import functools
  from tensorflow.python.platform import test
  from tensorflow.python.util import function_utils
label_desc: Use image node_id 2 for calling the FnArgsTest obj's underlying member method code with example usage: obj.test_callable() and returns: unknown