code: def _make_reserved_tokens_re(reserved_tokens):
      """Constructs compiled regex to parse out reserved tokens."""
      if not reserved_tokens:
          return None
      escaped_tokens = [_re_escape(rt) for rt in reserved_tokens]
      pattern = "(%s)" % "|".join(escaped_tokens)
      reserved_tokens_re = _re_compile(pattern)
      return reserved_tokens_re
  
imports: from __future__ import unicode_literals
  import abc
  import hashlib
  import json
  import re
  from tensorflow_datasets.core.utils.lazy_imports_utils import tensorflow
label_desc: Use image node_id 6 for calling a global function with example usage: _make_reserved_tokens_re(reserved_tokens) and returns: reserved_tokens_re, None