code: def _time_from_json(value, field):
      
      if _not_null(value, field):
          if len(value) == 8:  # HH:MM:SS
              fmt = _TIMEONLY_WO_MICROS
          elif len(value) == 15:  # HH:MM:SS.micros
              fmt = _TIMEONLY_W_MICROS
          else:
              raise ValueError("Unknown time format: {}".format(value))
          return datetime.datetime.strptime(value, fmt).time()
docs: Coerce 'value' to a datetime date, if set or not nullable