     return
 
 ff = (proto, tags) -> # fill with tags
-    for tagname in tags
-        pp proto, tagname if tagname
+    for tagname in tags when tagname
+        pp proto, tagname
     return
 
 

        create key, opts





clear = () ->
    cache = {}


    # set Tag class so we get the same results like create(…)
    xml.Tag = xml.opts.Tag = cache[key].Tag
    return xml


create = (key, opts) ->
    # get builder class from options
