rem: if (!oldN2) 
add: if (!ASSERT(oldN2, "Unable to change " + n1.Value + " -[" + a.Value + "]->, " + "because old value was not found.")) 
context: function rdf_change (n1, a, n2){    var oldN2 = this.ds.GetTarget (n1, a, true);    if (!oldN2)    {        dd ("** Unable to change " + n1.Value + " -[" + a.Value + "]->, " +            "because old value was not found.");        return null;    }        return this.ds.Change (n1, a, oldN2, n2);    }
meta: 1567	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/1567/ec1f57a2df47ea77b6ce245c6e2bd99b25d52195/rdf.js/clean/xul/content/rdf.js