Inverting a conditional function

[Steven D'Aprano]

I frequently have a function which tests some condition, returning True 
or False, and want a function which reverses the condition.

If all I wanted was the result of calling the function, I could say 

    not condition(x)

and be done with it, but I want a new function. I've been doing this:

    lambda arg: not condition(arg)

which is okay, but its a bit long and adds the cost of an extra function 
call. Is there a better way?




-- 
Steven D'Aprano
"Ever since I learned about confirmation bias, I've been seeing
it everywhere." -- Jon Ronson