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: [189.429, -34.947, 43.067, -54.332, 201.917, 122.601, -2.714, 236.741, 28.755, 148.385]

87.89