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: [118.367, 16.948, 51.017, 145.402, 195.233, 217.214, -61.421]

97.537