Example of "bubble up" recursion

recurse.py

def traverse_backward():
    def recurse(i):
        if i == 0:
            return
        recurse(i - 1)
        print(i)
    recurse(5)


def traverse_forward():
    def recurse(i):
        if i == 0:
            return
        print(i)
        recurse(i - 1)
    recurse(5)


if __name__ == "__main__":
    traverse_forward() # Prints 5, 4, 3, 2, 1
    traverse_backward()  # Prints 1, 2, 3, 4, 5