code: def fmt(msg, *args, **kw):
      # type: (str, *Any, **Any) -> str
      
      global is_tty
  
      if len(args) or len(kw):
          msg = msg.format(*args, **kw)
  
      opcode_subst = '\x1b[\\1m' if is_tty else ''
      return re.sub(r'<(\d{1,2})>', opcode_subst, msg)
docs: Generate shell color opcodes from a pretty coloring syntax.