What is the origin of the song "Huang Yang Bian Tan" in the latest episode of One Man Down?

Huangyang Bianlian is a folk song from Yuandong, Chongqing, originating from Youyang County and Xiushan County, Chongqing. It is a valuable cultural resource for the Tujia people, and has been sung by many famous singers such as Li Shuangjiang and Jiang Dawei, and is included in almost every book on Chinese folk songs.