'Gets all receipts for a room, upto the given key.'

@defer.inlineCallbacks
def get_receipts_for_room(self, room_id, to_key):

    result = (yield self.store.get_linearized_receipts_for_room(room_id, to_key=to_key))
    if (not result):
        defer.returnValue([])
    defer.returnValue(result)
