code: def init_read_line(self):
          
          format_list = self._format_list
          self._re_cvt = self.match_input_fmt(format_list)
          regexp0_str = "".join([subs[0] for subs in self._re_cvt])
          self._regexp_str = regexp0_str
          self._re = re.compile(regexp0_str)
          self._match_exps = [
              subs[1] for subs in self._re_cvt if subs[1] is not None
          ]
          self._divisors = [subs[2] for subs in self._re_cvt if subs[2] is not None]
          self._in_cvt_fns = [
              subs[3] for subs in self._re_cvt if subs[3] is not None
          ]
          self._read_line_init = True
docs: init_read_line() initializes fields relevant to input matching