Given a list of positive integers that are sorted in ascending order, write a function median_num(nums : List[int]) → float that determines the median of the list.
Note: The median is the “middle number ” of a list if the length of the list is odd. The median is the “two middle numbers ” / 2 if the length of the list is even.
For example:
median_num([1,3,3,6,7,8,9]) → 6median_num([1,2,3,4,5,6,8,9]) → 4.5