How did Gretl turn prince florian fro clockwork int a boy Clockwork?

In the story "Gretl and the Magic Flute," Gretl turned Prince Florian from a clockwork prince into a real boy by playing the magic flute that had the power to make his heart beat again. The music from the flute resonated with his mechanical heart, causing it to come to life and turn him back into a human.