def Get(self):
_result = []
cars = Car.all(Car.owner==self.user, key=self.rootKey()).fetch()
for car in cars:
_car = car.json()
_car['expenses'] = []
for _exp in Expense.all(key=ndb.Key(Car, car.key.id())).fetch():
_car['expenses'].append(_exp.json())
_result.append(_car)
self.response.headers['Content-Type'] = "application/force-download; charset=utf-8"
self.response.headers['Content-Disposition'] = 'attachment; filename="car-expenses-%s.json"' % str(datetime.now())[:10]
self.response.write(json.dumps(_result))
