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: [6.87, 202.429, 9.703, 63.414, 225.898, 105.652, 234.083]

121.15