fibonacci

fib.py

def fibonacci(num):
    def _fib(n, p0=0, p1=1):
        if n == 0:
            return p1
        return _fib(n - 1, p1, p0 + p1)

    return _fib(num)

# another way, without external function
def fib(num, p0=0, p1=1):
    if n == 0:
        return p1
    return fib(num - 1, p1, p0 + p1)