base.py 文件源码

def __init__(self, precision=None, scale=None, asdecimal=True, **kw):
        if isinstance(self, (REAL, DOUBLE)) and \
            (
                (precision is None and scale is not None) or
                (precision is not None and scale is None)
            ):
            raise exc.ArgumentError(
                "You must specify both precision and scale or omit "
                "both altogether.")

        super(_FloatType, self).__init__(precision=precision,
                                         asdecimal=asdecimal, **kw)
        self.scale = scale