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.

Ex Input:
[131.164, 99.999, 138.488, 57.264, -40.069, -82.402, -42.836]

Ex Output:
37.373

Ex Input:
[45.112, 147.024, -15.583, 33.655, -60.031]

Ex Output:
30.035

Ex Input:
[-68.943, 227.288, 178.786]

Ex Output:
112.377