def check_group_whitelist(self, username):
        if not self.group_whitelist:
            return False
        for grnam in self.group_whitelist:
            try:
                group = getgrnam(grnam)
            except __HOLE__:
                self.log.error('No such group: [%s]' % grnam)
                continue
            if username in group.gr_mem:
                return True
        return False
dataset/ETHPy150Open jupyterhub/jupyterhub/jupyterhub/auth.py/LocalAuthenticator.check_group_whitelist