3.3B: Using while to Keep a Program Running

# Set variables
# Set conditions
# Check whether we should break
# out of the while statement.
# Use negative condition where
# we check if provided answer is incorrect.
# input() tells terminal to wait
# for user input.
# Set correct to True 
# Causes while loop to stop executing.
# If correct, print success message
# Use if statement to 
# check answer is correct.
# Exit message

release_year = '1991'
correct = False
while not correct:
        answer = input('When was Python first released? ')
        if answer == release_year:
            print('Congratulations! That is correct. ')
            correct = True
        else:
            print('No, that\'s not it. Try again\n')
print('Bye!')