Use the Min/Max pattern to write a function maximum_odd that finds the highest odd value in the list (consumes a non-empty list of numbers and returns a number). Use the provided helper function is_odd (that consumes a single number and returns a boolean indicating whether it is true or false). Do not change the helper function is_odd. Unit test both functions.

Note: You can assume there will always be at least one odd number in the list, and none of the numbers will be negative.