code: def _country_level_time_zones_for_number(numobj):
      
      cc = str(numobj.country_code)
      for prefix_len in range(TIMEZONE_LONGEST_PREFIX, 0, -1):
          prefix = cc[:(1 + prefix_len)]
          if prefix in TIMEZONE_DATA:
              return TIMEZONE_DATA[prefix]
      return _UNKNOWN_TIME_ZONE_LIST
docs: Returns the list of time zones corresponding to the country calling code of a number.
      Arguments:
      numobj -- the phone number to look up
      Returns a list of the corresponding time zones or a single element list with the default
      unknown time zone if no other time zone was found or if the number was invalid