Misleading Documentation
Misleading Documentation

It seems that while writing the README, (arguably the most important file of all open-source projects) you've slipped and used the wrong rule. 

If one attempts to run the proposed example code, they would be greeted with "NameError: global name 'is_hot' is not defined".
I fix that by renaming it to the correct "should_buy".

Also, I would mention somewhere that to use the lambda expression, one must use python2. The "max(candidates.iteritems(), key=lambda (key, inputs): should_buy.eval(**inputs))" will throw a syntax error in python3.

I've also removed the dots from the dictionary example, to enable easier copy-paste while testing the example.

I hope this helps all the people looking to get started with fuzzy sets!
swistakm/frules