code: def _validate_toolbar(s):
      s = ValidateInStrings(
          "toolbar",
          ["None", "toolbar2", "toolmanager"],
          ignorecase=True,
      )(s)
      if s == "toolmanager":
          _api.warn_external(
              "Treat the new Tool classes introduced in v1.5 as experimental "
              "for now; the API and rcParam may change in future versions."
          )
      return s
  
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 11 for calling a global function with example usage: _validate_toolbar(s) and returns: s