The most likely reason this passage was included at the end of the narrative is because the narrator is

the narrator closes the lantern tightly so the old man is

not awakened by the bright light

explanation:

hi there!

one thousand and one nights, also called the arabian nights is a collection of middle eastern tales compiled in arabic during the islamic golden age, dated from the 8th to the 14th century. this collection was compiled of largely middle eastern and indian stories with an uncertain date and autorship whose tales such as aladdin, ali baba and sinbad the sailor -these ones were the most popular ones, the ones that have almost become part of western folklore.

as in much medieval european literature, the stories contained in this collection are set within a frame story. its scene is central asia, as known as "the islands or peninsulae of india and china", where king shahryar kills his wife after discovering her infidelities and as well as any other who betrayed him.   then, loathing all womankind, he marries and kills his new wife each day until no more candidates could have been found. his vizier had two daughters, scheherezade and dunyazad. the elder one -scheherezade- having devised a scheme to save herself and the others insisted that her father needed to give her in marriage to the king. each evening, she used to tell a story leaving it incomplete and promising to finish it the following night. the stories kept the king very interested, so eager to hear evey ending of each story, that he puts off her execution from day to day and finally he decided to give up with his plan. these stories are contained within the collection of 1001 nights, the bulk of the text is in prose, although verse is usually used for songs and riddles to express better the heightened emotion of them.