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: [246.737, 248.17, -58.021, 103.791, 157.836, -37.1, 243.277, 62.463]

120.894