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: [210.352, -33.371, 96.94, 149.299, 128.468, 73.334, 221.988, 247.44, 130.441, 114.575]

133.947