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: [107.201, 20.191, 238.887, 237.174, 52.537, 99.85, 214.946]

138.684