Simple python object to json serialization

demo.py

import json
import pprint

class Brain:
	def __init__(self, iq):
		self.iq = iq	

class Person():
	def __init__(self, name=None, age=None, brain: Brain=None):
		self.age = age
		if brain:
			self.brain = Brain(**brain)
		self.name=name
	def toJSON(self):
 		return json.dumps(self, default=lambda o: o.__dict__, sort_keys=True, indent=4)

	@classmethod
	def from_dict(cls, dict):
		obj = cls()
		obj.__dict__.update(dict)
		return obj

person_string = '{"name": "Bob", "age": 25, "brain" : { "iq" : "100" }}'

person_dict = json.loads(person_string)

person_object = Person(**person_dict)

pprint.pprint(person_object.name)
pprint.pprint(person_object.brain)
pprint.pprint(type(person_object.brain))
pprint.pprint(person_object.brain.iq)

person_string_2 = person_object.toJSON()

ix = json.loads(person_string_2, object_hook=Person.from_dict)

pprint.pprint(type(ix.brain))
pprint.pprint(ix.brain.iq)
pprint.pprint(ix.name)

print("person3")
person_string_3 = """
{
    "age": 25,
    "brain": {
        "iq": "100"
    },
    "name": "Bob",
    "whatever": 42
}
"""

ix = json.loads(person_string_3, object_hook=Person.from_dict)

pprint.pprint(type(ix.brain))
pprint.pprint(ix.brain.iq)
pprint.pprint(ix.name)
pprint.pprint(ix.whatever)