Closures

We are going to use a function that simulates something long.

import time

def long_call(value:int):
    time.sleep(2)
    return value**2

This function calculates the square of the value but takes 2 seconds for that.

Activity

This function should be faster if called a second time with the same argument.

Modify that function so that on each call she stores the result. If she's called a second time with the same argument, she retunes the cached value instead of calculating it again.

Improvement

Extend the feature for all previous values.