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: [12.061, 106.618, -55.626, -28.064, 48.302, 125.589, 67.814]

39.528