On 07/03/2020 05:03 PM, Steven D'Aprano wrote:

     def clamp(value, lower, upper):
         """Clamp value to the closed interval lower...upper.

         The limits lower and upper can be set to None to
         mean -∞ and +∞ respectively.
         """
         if not (lower is None or upper is None):
             if lower > upper:
                 raise ValueError('lower must be <= to upper')
         if lower == upper is not None:
             return lower
         if lower is not None and value < lower:
             value = lower
         elif upper is not None and value > upper:
             value = upper
         return value

I'm having a hard time understanding this line:

           if lower == upper is not None:

As near as I can tell, `upper is not None` will be either True or False, 
meaning the condition will only ever be True if `lower` is also either True or 
False, and since I would not expect `lower` to ever be True or False, I expect 
this condition to always fail.  Am I missing something?

--
~Ethan~
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