Remove Duplicates

Given a sorted list of numbers, remove duplicates and return the new length. You must do this in-place and without using extra memory.

Input: [0, 0, 1, 1, 1, 2, 2].

Output: 3.

Your function should modify the list in place so the first 3 elements becomes 0, 1, 2. Return 3 because the new length is 3.