code: def testMapFuncMustReturnDataset(self, num_parallel_calls):
      def map_fn(x):
          return [x]
  
      with self.assertRaisesRegex(
          TypeError,
          "The `map_func` argument must return a `Dataset` object.",
      ):
          dataset_ops.Dataset.from_tensors(42).interleave(
              map_fn, num_parallel_calls=num_parallel_calls
          )
  
imports: import multiprocessing
  import os
  from absl.testing import parameterized
  import numpy
  from tensorflow.python.data.experimental.ops import testing
  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.data.ops import options
  from tensorflow.python.framework import combinations
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import sparse_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 10 for calling the InterleaveTest obj's underlying member method code with example usage: obj.testMapFuncMustReturnDataset(num_parallel_calls) and returns: list