Fetches the institute id of the RU

def fetch_inst_id(self):
        """ Fetches the institute id of the RU """
        try:
            for d in msgpack.unpack(urllib2.urlopen(
                    "%s/list/institutes?format=msgpack" % self.url)):
                if d['name'] == 'Radboud Universiteit Nijmegen':
                    return d['id']
        except IOError, e: # urllib2 exceptions are a subclass of IOError
            raise RuusterError(e)
        assert False