code: def validate_sketch(s):
      if isinstance(s, six.string_types):
          s = s.lower()
      if s == "none" or s is None:
          return None
      if isinstance(s, six.string_types):
          result = tuple([float(v.strip()) for v in s.split(",")])
      elif isinstance(s, (list, tuple)):
          result = tuple([float(v) for v in s])
      if len(result) != 3:
          raise ValueError(
              "path.sketch must be a tuple (scale, length, randomness)"
          )
      return result
  
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 35 for calling a global function with example usage: validate_sketch(s) and returns: result, None