[deathanatos]

That's a huge micro-optimization. For a trivial example of a class having the attributes "a", "b" and "c", and a dict of the same,

    In [4]: %timeit d['b']  # dict
    10000000 loops, best of 3: 42.7 ns per loop

    In [6]: %timeit f.b  # class using __slots__
    The slowest run took 30.10 times longer than the fastest. This could mean that an intermediate result is being cached.
    10000000 loops, best of 3: 44 ns per loop

    In [9]: %timeit b.b  # class using __dict__
    10000000 loops, best of 3: 48.1 ns per loop

You're talking <6ns per access; except in the very exceptional case where you know you need this, in Python of all languages, it's an over optimization. The maintainability of having the stupid-simple class vastly outweighs the speed.