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: [134.13, -75.35, 172.328, 228.515, 198.832, 197.949, 109.706, 63.086]

128.649