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: [198.458, -11.734, 214.543, -56.112, 214.139, -52.456, 29.492]

76.619