code: def _warn_if_deprecated(key):
      """
      Checks if `key` is a deprecated option and if so, prints a warning.
  
      Returns
      -------
      bool - True if `key` is deprecated, False otherwise.
      """
  
      d = _get_deprecated_option(key)
      if d:
          if d.msg:
              print(d.msg)
              warnings.warn(d.msg, FutureWarning)
          else:
              msg = "'{key}' is deprecated".format(key=key)
              if d.removal_ver:
                  msg += " and will be removed in {version}".format(
                      version=d.removal_ver
                  )
              if d.rkey:
                  msg += ", please use '{rkey}' instead.".format(
                      rkey=d.rkey
                  )
              else:
                  msg += ", please refrain from using it."
  
              warnings.warn(msg, FutureWarning)
          return True
      return False
  
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 15 for calling a global function with example usage: _warn_if_deprecated(key) and returns: False, True