def delete(self, doc):
        if doc.id is None:
            raise DatabaseException('Document does not have id')
        if doc.sid is None:
            try:
                rs = self.db.docs.remove({'id': doc.id}, safe=True)
                assert rs['n'] == 1
            except Exception as e:
                raise DatabaseException(e)
            return None
        doc.data = None
        return self.update(doc)
def process_weight(sym, arg, aux):
            for stride in RpnParam.anchor_generate.stride:
                add_anchor_to_arg(
                    sym, arg, aux, RpnParam.anchor_generate.max_side,
                    stride, RpnParam.anchor_generate.scale,
                    RpnParam.anchor_generate.ratio)