[yz@test-4 yz]$ python3
>>> import json
>>> s = '{"x": "123", "y": "456"}'
>>> r = json.loads(s)
>>> j = json.dumps(r, indent=None, ensure_ascii=False)
>>> print(j)
{"x": "123", "y": "456"}
>>> j = json.dumps(r, indent=None, ensure_ascii=False, separators=(',',':'))
>>> print(j)
{"x":"123","y":"456"}
>>> j = json.dumps(r, indent=None, ensure_ascii=False, separators=(', ',': '))
>>> print(j)
{"x": "123", "y": "456"}