Only after a thousand calls did he come out, still holding a pipa to cover his face! From which article?

This sentence came from Bai Juyi's "Fu De Gu Yuan Cao Farewell" in the Tang Dynasty. The original text was as follows: The grass on the plain withers and thrives once a year. The wildfire never ends, and the spring breeze blows, it grows again. The far-off fragrance encroaches on the ancient road, the clear green connecting the deserted city. And send the king's grandson away, full of parting feelings. I come out after a thousand calls, still holding a pipa half covering my face. I turn to the vermilion pavilion, and the low door of the palace is illuminated by the light, sleepless. Should not hate, what long will it last until the time of parting? Outside the pavilion, by the ancient road, fragrant grass and green sky. The evening breeze blows the willows, and the flute's sound remains the setting sun beyond the mountains. At the end of the sky, at the corner of the earth, my friends are half gone. A ladle of wine to the end of the world road at this time this night embarrassed. This was a farewell poem that described the poet's mood and scenery when he bid farewell to his good friend. Among them," After a thousand calls, I finally come out, but I still hold the pipa and cover my face halfway " depicted the poet waiting in front of his friend for a long time, but his friend never showed up.