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.

[-17.026, 165.89]
74.432

[224.567, -42.213, 232.017]
138.124

[5.895, 229.727]

117.811