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: [18.274, 29.409, 247.641, 209.428, 135.158, 44.039, 227.479, 117.44, 114.637]

127.056