a=[1,2,3,4].reverse() - why "a" is None?

[Nadav Chernin]

	Chris Withers wrote:

	...becauase you were looking for:

	reversed([1,2,3,4])

OK, but my question is generic. Why when I use object's function that
changed values of the object, I can't to get value of it on the fly
without writing additional code?

>>> a=[1,3,2,4]
>>> a.sort()
>>> a.reverse()
>>> a
[4, 3, 2, 1]

Why I can't a==[1,3,2,4].sort().reverse() ?