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: [-31.505, -25.291, -88.299, 23.561, 182.747, 144.445, 84.875]

41.505