code: def fontInfoPostscriptStemsValidator(values):
      """
      Version 2+.
      """
      if not isinstance(values, (list, tuple)):
          return False
      if len(values) > 12:
          return False
      for value in values:
          if not isinstance(value, numberTypes):
              return False
      return True
  
imports: import calendar
  from io import open
  import fs.base
  import fs.osfs
  from collections.abc import Mapping
  from fontTools.ufoLib.utils import numberTypes
label_desc: Use image node_id 18 for calling a global function with example usage: fontInfoPostscriptStemsValidator(values) and returns: True, False, False, False