(defmacro with-osm (stream &body body)
  `(progn
     (format ,stream "~a~%~a~%"
             "<?xml version='1.0' encoding='UTF-8'?>"
             "<osm version=\"0.6\" generator=\"osmium/1.5.1\">")
     ,@body
     (format ,stream "~&</osm>~%")))