Who is the author of Huaqing Palace quatrains?

On the top of the mountain, the palace doors are opened layer by layer. The post horse runs so fast that it can't see clearly what's inside. Only Yang Guifei looked at the mountain from a distance and smiled happily when she knew that her favorite litchi had arrived.

This epic was written by Du Mulu when he arrived in Chang 'an via Huaqing Palace, feeling that Tang Xuanzong and Yang Guifei were extravagant and misunderstood their own country. Huaqing Palace was once a playground for Emperor Xuanzong of the Tang Dynasty and Yang Guifei. According to "New Tang Book"? "Biography of Yang Guifei" records: "I love lychee, and I will be born with it. She went to Wan Li Road, and her taste has not changed. She has arrived in the capital. " Therefore, on the way from Sichuan to Chang 'an, many policemen were exhausted and the post horses fell dead. Crossing the quatrains of the Qing Palace intercepted this historical fact, attacked the arrogance, extravagance and ignorance of feudal rulers, satirized the present with history and warned the monarch.