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: [3.654, -23.636, 142.103, 198.956, 153.939, 127.679, 4.916, 105.643, 94.915, 56.81]

86.498