Memoize pattern implementation

memoize.py

def memoize(f):
    cache = {}
    def decorated(n):
        if n in cache:
            return cache[n]
        else:
            cache[n] = f(n)
        return cache[n]
    return decorated


@memoize
def factorial(n):
    if n <= 0:
        return 1
    return n*factorial(n-1)


@memoize
def fibonacci(n):
    if n<=1:
        return 1
    return fibonacci(n-1)+fibonacci(n-2)


print factorial(5)
print fibonacci(3)