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: [-15.742, 162.92, 41.11, -19.597, 75.539, 41.934, 120.605]

58.11