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: [173.052, -89.677, 156.862, -69.941, 222.397, 62.835, 230.201, 203.191, 43.838]

103.64