memoization

def memoize(f):
    t = dict()
    def lambda1(n):
        if n not in t:
            t[n] = f(n)
        return t[n]

    return lambda1

fibfast = memoize(lambda n : 1 if n < 2 else fibfast(n-1) + fibfast(n-2))


print(fibfast(1))
print(fibfast(2))
print(fibfast(3))
print(fibfast(4))
print(fibfast(5))