json_dumps.py

class JSONConverter:
	@classmethod
	def json_dumps(cls, obj) -> str:
		return str(cls._json_dumps(obj))
	
	@classmethod
	def _json_dumps(cls, obj):
		if isinstance(obj, list):
			return [cls._json_dumps(el) for el in obj]
		elif isinstance(obj, dict):
			return {
				cls._json_dumps(key): cls._json_dumps(value)
				for key, value in obj.items()
			}
		else:
			if isinstance(obj, bool):
				return str(obj).lower()
			elif obj is None:
				return 'null'
			else:
				return str(obj)
		

json_dumps = JSONConverter.json_dumps

print(json_dumps([1, [1, 2], {1: None}, [1, {2: True}]]))

assert json_dumps([1, [1, 2], {1: None}, [1, {2: True}]]) == "['1', ['1', '2'], {'1': 'null'}, ['1', {'2': 'true'}]]"