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: [72.326, -74.6, 127.566, -54.848, 198.529, -44.061, -28.155]

28.108