code: def testChangingStateShape(self):
      def reduce_fn(x, _):
          # Statically known rank, but dynamic length.
          larger_dim = array_ops.concat([x[0], x[0]], 0)
          # Statically unknown rank.
          larger_rank = array_ops.expand_dims(x[1], 0)
          return larger_dim, larger_rank
  
      reducer = grouping.Reducer(
          init_func=lambda x: ([0], 1),
          reduce_func=reduce_fn,
          finalize_func=lambda x, y: (x, y),
      )
  
      for i in range(1, 11):
          dataset = (
              dataset_ops.Dataset.from_tensors(np.int64(0))
              .repeat(i)
              .apply(grouping.group_by_reducer(lambda x: x, reducer))
          )
          dataset_output_shapes = dataset_ops.get_legacy_output_shapes(
              dataset
          )
          self.assertEqual([None], dataset_output_shapes[0].as_list())
          self.assertIs(None, dataset_output_shapes[1].ndims)
          get_next = self.getNext(dataset)
          x, y = self.evaluate(get_next())
          self.assertAllEqual([0] * (2**i), x)
          self.assertAllEqual(np.array(1, ndmin=i), y)
          with self.assertRaises(errors.OutOfRangeError):
              self.evaluate(get_next())
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.python.data.experimental.ops import grouping
  from tensorflow.python.data.kernel_tests import checkpoint_test_base
  from tensorflow.python.data.kernel_tests import test_base
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 5 for calling the GroupByReducerTest obj's underlying member method code with example usage: obj.testChangingStateShape() and returns: larger_dim,  larger_rank