JSON Serializer for Python objects not serializable by default (date and datetime)

json_serializer.py

import json
from datetime import date, datetime

def to_json(obj):
    '''JSON serializer for objects not serializable by default'''

    if isinstance(obj, (datetime, date)):
        return obj.isoformat()
    raise TypeError (f'Type {type(obj)} not serializable')

data = {'today': date.today(), 'time': datetime.now(), 'life': 42}
json_data = json.dumps(data, default=to_json)

print(data)
print(json_data)