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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _use(cls, ec):
 """ underly implement of use """

        # class ConnectModel(cls):
        #     pass
        ConnectModel = type(cls.__name__, (cls,), {})

        ConnectModel.tablename = cls.tablename
        ConnectModel._base_class = cls
        if isinstance(ec, (str, unicode)):
            ConnectModel._engine_name = ec
        elif isinstance(ec, Session):
            ConnectModel._engine_name = ec.engine_name
            ConnectModel._connection = ec
        return ConnectModel