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: [-35.143, -11.091, -16.798, 9.943, -57.364, 14.753, 6.114, 138.351]

6.096