normalise list python

>>> a = [2,4,10,6,8,4]
>>> amin, amax = min(a), max(a)
>>> for i, val in enumerate(a):
...     a[i] = (val-amin) / (amax-amin)
...
>>> a
[0.0, 0.25, 1.0, 0.5, 0.75, 0.25]