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: [12.143, 21.628, 189.093, 206.713, 58.781, 215.809, 155.751, 125.477, 35.335]

113.414