Write a method that finds the sum of all the products of consecutive pairs of integers from 'first' to 'last'. For example, if first=4 and last=6 the method returns 50 because 4*5 + 5*6 = 50. Note that either parameter can be negative. Also you may assume first<last will always be true. Look at the test data for additional examples. Do not worry about getting a sum greater than the maximum possible integer value as none of the test data will cause that to happen.