I would like to find the relative path between two directories on my system.

**Example:**

If I have `pathA == <pathA>` and `pathB == <pathA>/dir1/dir2`, the relative path between them will be `dir1/dir2`.

How could I find it in python? Is there a tool I could use?

If **pathB** is contained in **pathA**, I could just do `pathB.replace(pathA, '')` to get this relative path, but what if **pathB** isn't contained in **pathA**?