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.

Example Input: [127.522, 232.86, 46.593]
Example Output: 135.658

Example Input: [-50.144, 0.802]
Example Output: -24.671

Example Input: [125.67, 5.514, 161.93, 107.05, 118.949, 233.815, 230.211]
Example Output:
140.448