Sequencing animations

alice1.animate(aliceTumbling, aliceTiming).finished

.then(() => alice2.animate(aliceTumbling, aliceTiming).finished)

.then(() => alice3.animate(aliceTumbling, aliceTiming).finished)

.catch(error => console.error(Error animating Alices: ${error}));

Hello, could you explain what finished is here for?