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: [64.98, -23.968, 107.113, -88.05, 48.489, 71.254, 103.289]

40.444