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: [-91.439, 241.636, 17.219, 126.501, 234.462, 184.828, -34.478]

96.961