code: def mark(self, digits: int = None) -> float:
          
  
          self._mark[:] = [self._mark[1], time()]
          rv = self._mark[1] - self._mark[0]
  
          if digits is not None and digits > 0:
              rv = round(rv, digits)
          elif digits == 0 or self._digits == 0:
              rv = int(rv)
          elif self._digits is not None and self._digits > 0:
              rv = round(rv, self._digits)
  
          return rv
docs: Return time in seconds since last mark, reset, or construction.
  
          :param digits: number of fractional decimal digits to retain (default as constructed)