code: def colon():
      
      return RegexBuilder(
          pattern_args=symbols.COLON,
          pattern_func=lambda x: r"(?<!\d){}".format(x)).regex
docs: Colon case.
  
      Match a colon ":" only if not preceeded by a digit.
      Mainly to prevent a cut in the middle of time notations e.g. 10:01