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: [103.663, -40.655, 59.867, -7.683, -63.184, -39.383, 134.187, 87.706]

29.315