j = """
{
    "Address": {
        "House_Number": 2,
        "State": "MA",
        "Street_Number": 13
    },
    "Name": "John"
}
"""
employee = json.loads(j, object_hook=class_mapper)
print((employee.name, employee.address.house_number, employee.address.
    street_number, employee.address.state))
How to load JSON data into nested classes?