code: def testOpCall_ReturnsOpNode(self):
      result = Foo(DUMMY_INPUT_NODE, foo=42)
      self.assertIsInstance(result, resolver_op.OpNode)
      self.assertEqual(repr(result), "Foo(Dict(x=Input()), foo=42)")
  
imports: import copy
  from typing import Optional, Mapping, Set
  import tensorflow
  from tfx.dsl.input_resolution import resolver_op
  import tfx.types
  from tfx.types import standard_artifacts
label_desc: Use image node_id 2 for calling the ResolverOpTest obj's underlying member method code with example usage: obj.testOpCall_ReturnsOpNode() without return types