code: def _empty_or_null(feature: Optional[tf.train.Feature]) -> bool:
      """True if feature is None or holds no values."""
      if feature is None:
          return True
      if (
          len(feature.bytes_list.value)
          + len(feature.int64_list.value)
          + len(feature.float_list.value)
          == 0
      ):
          return True
      return False
  
imports: from typing import Any, Dict, Iterable, Iterator, List, Optional, Tuple, Union
  import apache_beam
  import farmhash
  import numpy
  import tensorflow
  from tensorflow_data_validation import constants
  from tensorflow_data_validation import types
  from tensorflow_data_validation.utils import artifacts_io_impl
  from tensorflow_data_validation.skew.protos import feature_skew_results_pb2
label_desc: Use image node_id 6 for calling a global function with example usage: _empty_or_null(feature) and returns: False, True, True