code: def validate_fontstretch(s):
      stretchvalues = [
          "ultra-condensed",
          "extra-condensed",
          "condensed",
          "semi-condensed",
          "normal",
          "semi-expanded",
          "expanded",
          "extra-expanded",
          "ultra-expanded",
      ]
      # Note: Historically, stretchvalues have been case-sensitive in Matplotlib
      if s in stretchvalues:
          return s
      try:
          return int(s)
      except (ValueError, TypeError) as e:
          raise ValueError(f"{s} is not a valid font stretch.") from e
  
imports: import ast
  from functools import lru_cache, reduce
  from numbers import Real
  import operator
  import os
  import re
  import numpy
  from matplotlib import _api, cbook
  from matplotlib.cbook import ls_mapper
  from matplotlib.colors import Colormap, is_color_like
  from matplotlib._fontconfig_pattern import parse_fontconfig_pattern
  from matplotlib._enums import JoinStyle, CapStyle
  from cycler import Cycler, cycler
label_desc: Use image node_id 23 for calling a global function with example usage: validate_fontstretch(s) and returns: s, int