code: def testFromStructure(self):
      test_cases = [
          {"shape": tensor_shape.TensorShape([])},
          {"shape": tensor_shape.TensorShape([3])},
          {"shape": tensor_shape.TensorShape([1, 2])},
          {"shape": tensor_shape.TensorShape([1, 2, 3])},
      ]
  
      for test_case in test_cases:
          with ops.Graph().as_default() as g:
              iterator = iterator_ops.Iterator.from_structure(
                  dtypes.int64, output_shapes=test_case["shape"]
              )
              get_next = iterator.get_next()
              train_op = ops.get_collection_ref(ops.GraphKeys.TRAIN_OP)
              train_op.append(get_next)
              mg = meta_graph.create_meta_graph_def(graph=g)
              grappler_item = item.Item(mg)
              op_properties = grappler_item.GetOpProperties()
              self.assertEqual(
                  test_case["shape"],
                  op_properties["IteratorGetNext"][0].shape,
              )
  
imports: import numpy
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import iterator_ops
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import meta_graph
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.grappler import item
  from tensorflow.python.ops import array_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 21 for calling the GrapplerTest obj's underlying member method code with example usage: obj.testFromStructure() without return types