The Modules/_randommodule.c implements the 32-bit version of the MersenneTwister and its struct uses (unsigned long) for each of the 624 elements of the state vector.  

On a 32-bit build, the unsigned longs are 4 bytes.  However, on a 64-bit build, they are 8 bytes each eventhough only the bottom 32-bits are used.  This causes the random object to be twice as big as necessary. sys.getsizeof(_random.Random()) reports 5016 bytes.  This wastes memory, grinds the cache, and slows performance.

The (unsigned long) declaration should probably be replaced with (uint32_t).