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: [190.428, -96.979, -95.523, 50.089, 65.486, -98.869, -64.04]

-7.058