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: [-12.787, -46.359, -25.755, -36.59, 127.793, 150.091, 221.954, 78.029]

57.047