Como dizer a Python para voltar a uma linha anterior

def main(): #defines the area in indents that will be triggered with main()#
print('hi')
yn = input('Wanna loop back to the start? ')
if yn = 'yes':
main() #loops back to where we defined main#
main() #This starts the main loop, without this, main would just be defined but not run#
Sore Shark