What role does the description of the last sentence in Li Bai's seeing friends off play in expressing feelings?

I don't think you know Li Bai well enough. He has been pursuing freedom and relaxation all his life, so when he leaves his friends, he will not "touch towels with children" like ordinary people. He wanted to wave his hand and leave smartly. However, after all, it was farewell, so he used zebra songs to express his farewell.

The description of the last sentence expresses this contradiction of Li Bai, which is actually the characteristic of Li Bai's poetry and personality.

The description of the last sentence, its function is to outline the parting, render the environment, and introduce the reader into the parting scene.