code: def validate_hinting(s):
      if s in (True, False):
          return s
      if s.lower() in ("auto", "native", "either", "none"):
          return s.lower()
      raise ValueError(
          "hinting should be 'auto', 'native', 'either' or 'none'"
      )
  
imports: from __future__ import absolute_import, division, print_function
  import six
  from functools import reduce
  import operator
  import os
  import warnings
  import re
  from matplotlib import cbook, testing
  from matplotlib.cbook import mplDeprecation, deprecated, ls_mapper
  from matplotlib.fontconfig_pattern import parse_fontconfig_pattern
  from matplotlib.colors import is_color_like
  from cycler import Cycler, cycler
label_desc: Use image node_id 33 for calling a global function with example usage: validate_hinting(s) and returns: s, s