Sure, it works... but:
> Comparisons to singletons like None should always be done with is or is not, never the equality operators.
> 
> Also, beware of writing if x when you really mean if x is not None -- e.g. when testing whether a variable or argument that defaults to None was set to some other value. The other value might have a type (such as a container) that could be false in a boolean context!
from: http://www.python.org/dev/peps/pep-0008/

Also you can look at: http://stackoverflow.com/questions/7816363/if-a-vs-if-a-is-not-none