code: def fetch_room_ids(self, names):
          
          ret = {}
          names_set = set(names)
          try:
              for d in msgpack.unpack(urllib2.urlopen(
                      "%s/list/locations?format=msgpack" % self.url)):
                  name = d['name'].upper() # normalize: Hg -> HG
                  if name in names_set:
                      ret[name] = d['id']
          except urllib2.HTTPError, e:
              raise RuusterError(e)
          return ret
docs: Fetches the ids of the rooms with the given names