code: def _assert_single_captured_variable_argument(self, graph_def):
      # The single FunctionDef should have one argument, a captured variable
      (function_def,) = graph_def.library.function
      self.assertLen(function_def.signature.input_arg, 1)
      (function_arg,) = function_def.signature.input_arg
      self.assertEqual(
          dtypes.resource, dtypes.as_dtype(function_arg.type)
      )
  
imports: import os
  from tensorflow.core.protobuf import meta_graph_pb2
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.eager import backprop
  from tensorflow.python.eager import def_function
  from tensorflow.python.eager import wrap_function
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import importer
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor_spec
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import init_ops
  from tensorflow.python.ops import state_ops
  from tensorflow.python.ops import variable_scope
  from tensorflow.python.ops import variable_v1
  from tensorflow.python.ops import variables
  from tensorflow.python.ops.ragged import ragged_factory_ops
  from tensorflow.python.ops.ragged import ragged_tensor
  from tensorflow.python.platform import test
  from tensorflow.python.training import saver
label_desc: Use image node_id 4 for calling the WrapFunctionTest obj's underlying member method code with example usage: obj._assert_single_captured_variable_argument(graph_def) without return types