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: [-29.246, -24.597, 17.187, -68.121, -40.469, -28.26, 6.428, 38.379, -43.732, -35.752]

-20.818