def insert(self, doc, synced=False):
        doc.id = self.get_next_id()
        doc.synced = synced
        try:
            self.db.docs.insert(doc)
        except Exception as e:
            raise DatabaseException(e)
        return doc
def __init__(self, saddr, gaddr, glen):
        self.saddr = saddr
        self.gaddr = gaddr
        self.glen = glen
        if ip_address(self.saddr).version != \
           ip_address(self.gaddr).version:
            raise ValueError('Source and group addresses must be of the '
                             'same address family.')