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: [236.959, 159.123, 17.257, 241.561, 119.782, -3.56, -30.957]

105.738