Read this: Since ancient times, north Zhejiang and neighbouring south Jiangsu have been famed for their prosperity and opulence[citation needed], and simply inserting north Zhejiang place names (Hangzhou, Jiaxing, etc.) into poetry gave an effect of dreaminess, a practice followed by many noted poets. In particular, the fame of Hangzhou (as well as Suzhou in neighbouring Jiangsu province) has led to the popular saying: "Above there is heaven; below there is Suzhou and Hangzhou" (上有天堂，下有苏杭), a saying that continues to be a source of pride for the people of these two still prosperous cities.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): Inserting north Zhejiang names into poetry gave an effect of what?
dreaminess