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: [122.488, -73.626, 209.019, 118.305, 187.818, 93.208, 248.023, 93.695, 42.454, 225.39]

126.677