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: [-56.794, 59.597, 56.311, 79.049, 211.553, 106.134, 142.826]

85.525