Write a function named count_unique that accepts a list of integers as a parameter and returns a count of the number of unique values that occur in the list.
If the list contains multiple occurrences of the same element value, only one of those occurrences should count toward your total.
For example, if a list named numbers stores [7, 7, 2, 2, 1, 2, 2, 7], the call of count_unique(numbers) should return 3 because there are 3 unique values: 7, 2, and 1.
Constraints:
In solving this problem, do not create any other data structures such as lists, strings, etc., though you may create as many simple variables as you like.
Do not modify the list passed to your function as the parameter, such as by sorting or rearranging its element values.
