Custom JSON Serialization for Date and Decimal Objects

customserializer.py

from datetime import date, datetime, time
from decimal import Decimal

def to_json(python_object):
    """
    Adding in custom serialization for Date & Decimal objects.

    >>> import json
    >>> from datetime import date, datetime, time
    >>> from decimal import Decimal
    >>> json.dumps({'adatetime': datetime(2012, 1, 1, 12, 1, 1)}, default=to_json)
    '{"adatetime": "2012-01-01 12:01:01"}'
    >>> json.dumps({'adate': date(2012, 1, 1)}, default=to_json)
    '{"adate": "2012-01-01"}'
    >>> json.dumps({'atime': time(12, 1, 1)}, default=to_json)
    '{"atime": "12:01:01"}'
    >>> json.dumps({'adecimal': Decimal('1.01')}, default=to_json)
    '{"adecimal": "1.01"}'
    """
    if (isinstance(python_object, date)
        or isinstance(python_object, datetime)
        or isinstance(python_object, time)):
        return str(python_object)
    if isinstance(python_object, Decimal):
        return python_object.to_eng_string()
    raise TypeError(repr(python_object) + ' is not JSON serializable')

if __name__ == '__main__':
    import doctest
    doctest.testmod()