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: [-81.432, -63.059, 150.144, 55.203, 215.405, -89.797, 72.946]

37.059