Write a function named num_unique that accepts a sorted list of integers as a parameter and that returns the number of unique values in the list.
The list is guaranteed to be in sorted order, which means that duplicates will be grouped together.
For example, if a variable called lst stores the following values:
lst = [5, 7, 7, 7, 8, 22, 22, 23, 31, 35, 35, 40, 40, 40, 41]
then the call of num_unique(lst) should return 9 because this list has 9 unique values (5, 7, 8, 22, 23, 31, 35, 40 and 41).
It is possible that the list might not have any duplicates.
For example if list instead stored this sequence of values:
lst = [1, 2, 11, 17, 19, 20, 23, 24, 25, 26, 31, 34, 37, 40, 41]
Then a call on the function would return 15 because this list contains 15 different values.
If passed an empty list, your function should return 0.
Remember that you can assume that the values in the list appear in sorted (nondecreasing) order.
