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: [237.236, -47.943, 172.797, 103.68, 170.427, 224.622, 59.225, -50.297, 139.341]

112.121