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: [136.903, 55.906, 61.519, 224.5, 94.211, 148.896, 90.372]

116.044