How to access Nested function from outside?

def func_a():
    print('Task triggered for function A')

    def func_b():
        print('Task triggered for function B')

In this case, we cannot call func__b from outside. We can only access 

func_b() from inside of func_a().

def func_a():
    print('Task triggered for function A')

    def func_b():
        print('Task triggered for function B')

    func_b()
func_a()

To overcome this, we can return func_b as shown below:

def func_a():
    print('Task triggered for function A')

    def func_b():
        print('Task triggered for function B')

    # Notice, I am only providing the function name
    return func_b


task_b = func_a()
task_b()