Definition: In this task you will be given a list of numbers and you need to find the mean (average) of that list. The mean of a list can be found by summing every number in the list then dividing the result by the size of that list. The output should be rounded to 3 decimal places.
Input: [-9.715, -24.028, 111.091, -23.445, -20.084, 210.407, 36.112, 59.561]

42.487