HTTP/1.1 500 Internal Server Error Date: Fri, 13 Dec 2019 03:11:56 GMT Server: CL-HTTP/70.217 (LispWorks; 2.1.7) Connection: close Content-Type: text/html; charset=ISO-8859-1 Transfer-Encoding: chunked

In 1+ of (NIL) arguments should be of type NUMBER.