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: [-1.836, 181.786, 201.995, 236.588, 231.912, 4.96, -25.283, 157.641, 223.189, 157.143]

136.81