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: [126.453, 169.516, 109.837, 208.695, 113.906, 56.894, 171.345, 126.81]

135.432