Where does the poem "Things I Have Done" come from?

"Poems I Have Done" is from the writer Yan Qi.

The content of the poem is as follows:

During the day, I trimmed branches, swept fallen leaves, and combed the feathers of herons. At night, I helped the rivers stop coughing, flattened the moonlight, and helped the stars correct their coordinates. , I have done many things alone. I am quieter than the stars, the land, and the ocean. I no longer think about you. I go for a walk by the lake and step on my own shadow.