The mode of a group of numbers is the value (or values) that occur most often (values have to occur more than once). Given a sorted list of numbers, return a list of all modes in ascending order.
mode([4, 5, 6, 6, 6, 7, 7, 9, 10]) ➞ [6]
mode([4, 5, 5, 6, 7, 8, 8, 9, 9]) ➞ [5, 8, 9]
mode([1, 2, 2, 3, 6, 6, 7, 9]) ➞ [2, 6]
In this challenge, all group of numbers will have at least one mode.