- http://stackoverflow.com/questions/944700/how-to-check-for-nan-in-python/944712#944712
::
In [1]: nan = float('nan')
In [2]: nan is nan
Out[2]: True
In [3]: nan == nan
Out[3]: False
- http://stackoverflow.com/questions/15977808/why-dont-methods-have-reference-equality
- http://stackoverflow.com/questions/3877230/why-does-id-id-and-id-id-in-cpython
- http://stackoverflow.com/questions/306313/pythons-is-operator-behaves-unexpectedly-with-integers