code: def guess_pygments_highlighter(filename):
      
      try:
          from pygments.lexers import get_lexer_for_filename, get_lexer_by_name
      except Exception:
          return TextSH
      root, ext = os.path.splitext(filename)
      if ext in custom_extension_lexer_mapping:
          try:
              lexer = get_lexer_by_name(custom_extension_lexer_mapping[ext])
          except Exception:
              return TextSH
      else:
          try:
              lexer = get_lexer_for_filename(filename)
          except Exception:
              return TextSH
      class GuessedPygmentsSH(PygmentsSH):
          _lexer = lexer
      return GuessedPygmentsSH
docs: Factory to generate syntax highlighter for the given filename.
  
      If a syntax highlighter is not available for a particular file, this
      function will attempt to generate one based on the lexers in Pygments.  If
      Pygments is not available or does not have an appropriate lexer, TextSH
      will be returned instead.