def METHOD_NAME(self, mock_client):
    keys = [b"mykey1", b"mykey2"]
    self.backend.mget(keys)
    mock_client.ReadDocument.assert_has_calls(
        [call("dbs/celerydb/colls/celerycol/docs/mykey1",
              {"partitionKey": "mykey1"}),
         call().get("value"),
         call("dbs/celerydb/colls/celerycol/docs/mykey2",
              {"partitionKey": "mykey2"}),
         call().get("value")])