Solve: Array Sum (Two Dimensional)

Created By: Geoffrey Challen

/ Version: 2020.9.0

Declare and implement a function called arraySum that receives a nullable two-dimensional double array (Array<DoubleArray>?) values as its only parameter and returns the sum of the values in the array as a Double. If the array is null you should return 0 (as a Double). None of the inner arrays will be null.