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: [-31.438, 212.105, -57.043, 100.978, 200.208, -57.742, 54.525, 48.054]

58.706