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: [10.631, 163.267, 136.722, 151.677, 121.448, 213.687, -18.511, -11.91, 232.959, 46.147]

104.612