code: def _evalTimeStd(self, datetimeString, sourceTime):
          
          s = datetimeString.strip()
          sourceTime = self._evalDT(datetimeString, sourceTime)
  
          # Given string is in the format HH:MM(:SS)
          yr, mth, dy, hr, mn, sec, wd, yd, isdst = sourceTime
  
          m = self.ptc.CRE_TIMEHMS.search(s)
          if m is not None:
              hr, mn, sec = _extract_time(m)
          if hr == 24:
              hr = 0
  
          # time validation
          if hr < 24 and mn < 60 and sec < 60:
              sourceTime = (yr, mth, dy, hr, mn, sec, wd, yd, isdst)
              _pop_time_accuracy(m, self.currentContext)
  
          return sourceTime
docs: Evaluate text passed by L{_partialParseTimeStd()}