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: [130.217, 188.836, 207.591, 65.531, 145.61, 152.128, -36.543]

121.91