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: [-2.577, 195.355, -15.036, 213.694, 165.693, -66.406, -99.812, 55.565, -49.103, 58.171]

45.554