code: def example_alt_alleles(example, variant=None):
      """Gets a list of the alt alleles in example."""
      variant = variant if variant else example_variant(example)
      return [
          variant.alternate_bases[i]
          for i in example_alt_alleles_indices(example)
      ]
  
imports: import json
  from typing import Optional
  from absl import logging
  import numpy
  import tensorflow
  from deepvariant.protos import deepvariant_pb2
  from third_party.nucleus.io import sharded_file_utils
  from third_party.nucleus.io import tfrecord
  from third_party.nucleus.protos import variants_pb2
  from tensorflow.core.example import example_pb2
label_desc: Use image node_id 4 for calling a global function with example usage: example_alt_alleles(example, variant) and returns: unknown