code: def test_invalid_strings(self, data_format):
      with self.assertRaisesRegex(
          ValueError,
          f"Unable to extract channel information from '{data_format}'.",
      ):
          utils.get_channel_index(data_format)
  
imports: from absl.testing import absltest
  from absl.testing import parameterized
  from haiku._src import test_utils
  from haiku._src import utils
  import jax.numpy
  import numpy
label_desc: Use image node_id 3 for calling the ChannelIndexTest obj's underlying member method code with example usage: obj.test_invalid_strings(data_format) without return types