[yz@test-4 yz]$ python3
>>> import rapidjson as json
>>> s = '{"x": "123", "y": "456"}'
>>> r = json.loads(s)
>>> j = json.dumps(r, indent=None, ensure_ascii=False, separators=(', ',': '))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'separators' is an invalid keyword argument for rapidjson.dumps()