why python has "else" in "for-else" and "while-else"
===

I am a python starter.
I find that the "else" in “for-else” and "while-else" is unnecessary at all.
Because "for" and "while" will finally run to "else",and we can use the usual lines instead.

For example:

    for i in range(1, 5):
        print i
    else:
        print 'over'
and

    for i in range(1, 5):
        print i
    print 'over'
is the same.

So why python has "else" in "for-else" and "while-else"?
 