The average without the worst

Problem

Three grades arrive in a list and the teacher forgives the lowest one: the average is taken from the other two.

With [6, 10, 8] the 6 is dropped and you return 9.0, the average of 10 and 8.

If the bottom is a tie, like in [7, 7, 9], only one grade is forgiven and the average is 8.0.

Three grades always arrive, they are always whole numbers, and the result can end in half a point.

Examples

• The lowest comes first

  [6, 10, 8] → 9

• The lowest in the middle

  [5, 4, 9] → 7

• Half a point

  [8, 9, 6] → 8.5

Besides these, the challenge has hidden tests that are revealed when you submit your solution.

You start with this

def best_average(grades):
    pass

function bestAverage(grades) {
}