Write a method that returns a string made up of all the letters from 'first' to 'last'. The two character parameters will either both be upper-case letters or both be lower-case letters. Also, 'first' will always come before 'last' alphabetically or will be the same letter as 'last'. You do not need to check for these conditions. You may assume these conditions as preconditions. For example, if 'first' is 'D' and 'last' is 'H' you would return the string "DEFGH". Look at the test data for additional examples. NOTE: You MUST use a loop of some kind to solve this problem!