>>> def fill():
...     for x in range(1000000):
...             l = [x]*1000
...
>>> x = time.time(); fill(); print time.time()-x
6.86840891838
>>> def fill():
...     for x in range(1000000):
...             t = (x)*1000
...
>>> x = time.time(); fill(); print time.time()-x
0.178025007248