Write a function named distance that takes four parameters: the x$-$ and y$-$coordinates of the first point, followed by the x$-$ and y$-$coordinates of the second point. It should return the distance between those two points, using the Pythagorean Theorem, for which you will need to import the mathLinks to an external site. module and use the math.sqrt$()$ function.

Example$1$: d $=$ distance$(3,5,-1,2)$; Your function should return d $=5$

Example $2$: d $=$ distance$(0,0,0,0)$; Your function should return d $=0$

$2.$ Write a main function that will execute and call the distance function if the file is run as a script, but not if the file is imported into another file. Test it out by running it as a script and by creating another file that imports it and running that file as a script.