NotImplemented used in Decimal

Steven D'Aprano steve at
Sat Apr 24 11:56:35 CEST 2010

On Fri, 23 Apr 2010 23:51:39 -0700, Chris Rebert wrote:

> If the conversion to Decimal in  _convert_other() fails, the operator
> method returns NotImplemented to signal to the interpreter that Decimal
> doesn't know how to do the requested operation with an operand of the
> given type; the interpreter will fall back by calling the reflected
> method of the other operand. 

I knew that works with comparisons __eq__ etc, but somehow I had a mental 
blank about arithmetic operators! Yes, you're right, and the docs say so 
explicitly. Somehow I had convinced myself that NotImplemented only 
worked with comparisons.


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