code: def test_maybe_generate_sharded_filenames(self, filespec, expected):
      self.assertEqual(
          io.maybe_generate_sharded_filenames(filespec), expected
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import absltest
  from absl.testing import parameterized
  from third_party.nucleus.io import sharded_file_utils
  from third_party.nucleus.testing import test_utils
label_desc: Use image node_id 3 for calling the IOTest obj's underlying member method code with example usage: obj.test_maybe_generate_sharded_filenames(filespec, expected) without return types