Write a method that returns the sum of all the integers from 'low' up to and including 'high'. As preconditions you may assume that 'low' is less than or equal to 'high' and that the sum will not exceed the maximum value that can be stored in an integer. For example, if 'low' is -2 and 'high' is 4 you would return a 7 since (-2)+(-1)+(0)+(1)+(2)+(3)+(4) = 7. Look at the test data for other examples.