What will happen if we pass the number 4 first, and 16 after? The answer will be 0.25. But we don't want it to happen. We want a scenario where if we see that first < second, we swap the numbers and divide them. But we aren't allowed to change the function.

Let's create a decorator that will take the function as a parameter. This decorator will add the swipe functionality to our function.

1def swipe_decorator(func):
2    def swipe(first, second):
3        if first < second:
4            first, second = second, first
5        return func(first, second)
6
7    return swipe

Now we have generated a decorator for the divide() function. Let's see how it works.

1divide = swipe_decorator(divide)
2divide(4, 16)

The output is:

1The result is: 4.0

We have passed the function as a parameter to the decorator. The decorator "swiped our values" and returned the function with swiped values. After that, we invoked the returned function to generate the output as expected.

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def divide(first, second):

    print ("The result is:", first/second)

​

def swipe_decorator(func):

    def swipe(first, second):

        if first < second:

            first, second = second, first

        return func(first, second)

​

    return swipe

​

​

divide = swipe_decorator(divide)

divide(4, 16)