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: [202.404, 146.589, 153.668, 77.542, 134.445, 9.641, 181.602]

129.413