mapping multiple tables for one class

I'm doing something to finish the horizontal shard job.
The examle is sharding to multiple database . And i just do it for
multipls tables in one database.

there is many tables just like  msg_00,msg_01..... msg_99
defind  the class like  Msg()  map the tables .

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m = Msg
number = int(uid)%100
tablename = 'msg_%02d'%(number)
m.__uuid__ = uid
m.__table__.name = tablename
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now  "m" mapping the table msg_xx .
It works in the select sql.
but fail in the session.add(newmessage) because the sqlalchemy has cache
connection .  event one table is  Table(msg_00) and another is Table
(msg_01)

So, i edit the memo key .   then there is diff  insert object .

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It's simple change and useful. It‘s safe for the old version .
sorry for my poor english.