{'val': {'args': ['9.3456789098765434987654567'], '__type__':
    'decimal.Decimal'}, 'now': {'args': [2014, 4, 29, 11, 44, 57, 971600],
    '__type__': 'datetime.datetime'}}
{'val': Decimal('9.3456789098765434987654567'), 'now': datetime.datetime(
    2014, 4, 29, 11, 44, 57, 971600)}
Python JSON encoder to support datetime?