After completing 6 testscores lettergrade (and watching the video), fork your repl as 6b and solve the English semantic dilemma occurring when just 1 assignment is graded and an A or F grade is displayed and you do not want to say 'a A' or 'a F' but rather 'an A' or 'an F inside your output string. Create variables for assignment_s and a_an which deterimine when to use assignments (with or without an 's') and when to use 'an' in front of the letter grade instead of ' a