'Return True if db_user/db_password is already an admin user.'

def _check_user_provided(self):

    client = pymongo.MongoClient(host, port, username=db_user, password=db_pwd, serverSelectionTimeoutMS=100, **self.ssl_client_options)
    try:
        return (db_user in _all_users(client.admin))
    except pymongo.errors.OperationFailure as e:
        msg = e.details.get('errmsg', '')
        if ((e.code == 18) or ('auth    fails' in msg)):
            return False
        else:
            raise
