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: [-63.418, 15.605, 36.936, -47.92, -99.465, 122.239, -35.633, 52.687]

-2.371