Functions - General Questions

What is the output of the following code?

def outer():
    count = 0
    def inner():
        nonlocal count
        count += 1
        return count
    return inner
c = outer()
c()
print(c())

What is the output of the following code?

def add(a, b=10):
    return a + b
print(add(5), add(5, 1))

What is the output of the following code?

def f(items=[]):
    items.append(1)
    return len(items)
f(); f()
print(f())

What is a docstring?

What is the output of the following code?

def fact(n):
    return 1 if n <= 1 else n * fact(n - 1)
print(fact(5))