The file is being locked after read-csv is called

[suicodave]

 (defn read-csv [path as-vector?]
  (let [rows (csv-reader/read-csv path)
        final-rows (if (true? as-vector?) (vectorize-rows rows) rows)]
    (csv-reader/close! rows)
    final-rows))

I have this function called but when I try to rename the file, it will say that it is currently in use. How can I release it?