code: def _get_names(dirs):
      """Get alphabet and label names, union across all dirs."""
      alphabets = set()
      label_names = {}
      for d in dirs:
          for example in _walk_omniglot_dir(d):
              alphabet, alphabet_char_id, label, _, _ = example
              alphabets.add(alphabet)
              label_name = "%s_%d" % (alphabet, alphabet_char_id)
              if label in label_names:
                  assert label_names[label] == label_name
              else:
                  label_names[label] = label_name
      label_names = [label_names[k] for k in sorted(label_names)]
      return alphabets, label_names
  
file_path: datasets/tensorflow_datasets/image_classification/omniglot.py
imports: import os
  import numpy
  from tensorflow_datasets.core.utils.lazy_imports_utils import tensorflow
  import tensorflow_datasets.public_api
label_desc: Use image node_id 2 for calling a global function with example usage: _get_names(dirs) and returns: alphabets,  label_names