Get a list of shards belonging to this instance.

        :param bool add_shard: A boolean indicating whether to add a new shard to the specified
            instance.

def shards(self, add_shard=False):
        """Get a list of shards belonging to this instance.

        :param bool add_shard: A boolean indicating whether to add a new shard to the specified
            instance.
        """
        url = self._service_url + 'shards/'
        if add_shard:
            response = requests.post(url, **self._instances._default_request_kwargs)
        else:
            response = requests.get(url, **self._instances._default_request_kwargs)

        return response.json()