print('Welcome to our hours of study calculator! Easily determine how many hours you have to study based on the grade you want! Thank you for using my program! Have a great day.') #initalize variables run_again = 'Y' total_credits = 0 allstudents_studyhours = 0 total_students = 0 while run_again.upper() == 'Y':#Loop continues as long as user enters Y     full_name = ""     #str     first_name = ""     last_name = ""     full_name = ""     grade_wanted = ""     credits_taken = ""     #int          number_of_classes = 0     studyhours_needed = 0     total_number_studyhours_perstudent= 0           #list     grades = ['A','B','C','D','F']     first_name = input('Please enter your first name:') #1-Ask user's first_name     while first_name =="": #validate that the user entered a name.         print('You must enter a valid name:')         first_name = input('Please enter your first name:') #1A-Ask user's last_name     last_name = input('Please enter you last name:')       while last_name == "":#validate that the user entered a last name         print('You must enter a valid last name:')         last_name = input('Please enter you last name:')  #2-Ask user how many credits they are taking     credits_taken = input('Please enter number of credits youre taking:')         while not credits_taken.isdigit() or int(credits_taken) < 3 or int(credits_taken)> 18 or int(credits_taken) % 3:  #validation of credits each student is taking.         print('Enter a valid number of credits you are taking, if each class is 3 credits:')         credits_taken = input('Please enter number of credits youre taking:')        #3-Ask user what grade they would like to receive(assume same for all classes.)     grade_wanted = input('Please enter the grade wanted for your classes:')     while not grade_wanted.upper() in grades:          #validating grades         print( 'Please enter a valid grade:')         grade_wanted = input('Please enter the grade wanted for your classes:')     grade_wanted = grade_wanted.upper() ####Calculations ##4 We are calculating the total number of classes the student is taking     number_of_classes = (int(credits_taken) / 3) ##5 Calculating the total number of hours student will have to study, per class, to acheive the grade wanted. Assume the same for each class.     if grade_wanted == 'A':         studyhours_needed = 15     elif grade_wanted == 'B':         studyhours_needed = 12     elif grade_wanted == 'C':         studyhours_needed = 9     elif grade_wanted == 'D':         studyhours_needed = 6     else:         grade_wanted == 'F'         studyhours_needed = 0         ##6 Calculating the total number of hours the student must study for all classes.     total_number_studyhours_perstudent = (number_of_classes * studyhours_needed) ##7 We are going to display the following information to the user.         print('Name:',first_name + " "+ last_name)     print('Credits:', credits_taken)     print('Study Hours:',total_number_studyhours_perstudent)     print('Grade:', grade_wanted) ##8 Calc the total number of students who used the program.     total_students = total_students + 1 ##9 Calc total number of credits taken by all students who used the program.     total_credits = total_credits + int(credits_taken)    # print(total_credits) #10 Calc total number of study hours for all students who used the program.     allstudents_studyhours = total_number_studyhours_perstudent + allstudents_studyhours    # print(allstudents_studyhours) #11 This will determine if you would like to keep running the program, or quit.     run_again = input('Would you like to continue using the program? If yes, please enter Y, any other key will exit') #12 Calculate and display the following information to the user. print('Total Students:', total_students) print('Average Credits:', total_credits / total_students) print('Average Study Hours:', allstudents_studyhours / total_students)   I need this is function format. This question was refused because of name validation--it just has to be letters and a non null value. It has to be Python language, not C++.