number of ways to make change from coins without repetition

make_change.py

def make_change(amount, coins):
    coins.sort()

    def _make_change(amount, idx, result):
        if amount == 0:
            print result
            return
        for i in range(idx, len(coins)):
            coin = coins[i]
            if coin <= amount:
                #print "CALL: (%s,%s,%s)" % (amount - coin, i, result + [coin])
                _make_change(amount - coin, i, result + [coin])
    _make_change(amount, 0, [])

# example:
make_change(4, [1,2,3])
# [1, 1, 1, 1]
# [1, 1, 2]
# [1, 3]
# [2, 2]