python please

Write a program that will ask the user to enter a phrase and then repeatedly asks for starting and ending positions. Your program must operate exactly like this demonstration: Enter a phrase: Cafeteria food tastes terrible. Thank you. Now we'll carve it up. Enter starting and ending position numbers: 7 12 That slice is 'ia fo'. Again? y Enter starting and ending position numbers: 0 8 That slice is 'Cafeteri'. Again? y Enter starting and ending position numbers: 73 Invalid. The starting position must be less than the ending position. Again? n