code: def _is_deprecated(key):
      """Returns True if the given option has been deprecated"""
  
      key = key.lower()
      return key in _deprecated_options
  
imports: from collections import namedtuple
  from contextlib import contextmanager
  import re
  import warnings
  import pandas.compat
  from pandas.compat import lmap, map, u
label_desc: Use image node_id 11 for calling a global function with example usage: _is_deprecated(key) and returns: unknown