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: [129.847, 1.147, 221.868, 34.963, 23.464, 47.57, 213.896]

96.108