def __call__(self, *args, **kwargs):
        """Return initialized client instance."""
        key = "{0}{1}{2}".format(self.get_name(),
                                 str(args) if args else "",
                                 str(kwargs) if kwargs else "")
        if key not in self.cache:
            self.cache[key] = self.create_client(*args, **kwargs)
        return self.cache[key]
dataset/ETHPy150Open openstack/rally/rally/osclients.py/OSClient.__call__/original