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.

[17.197, 152.985, 73.815]
81.332

[125.332, 80.443]
102.887

[85.257, 200.513, -80.531, 133.813, 157.564, -47.638]

74.83