public Function(QName qname, Signature signature) {
this.fid = new FunctionIdentifier(VXQUERY, "{" + qname.getNamespaceURI() + "}" + qname.getLocalPart());
this.qname = qname;
this.signature = signature;
this.documentOrderPropagationPolicy = new DocumentOrderYESPropagationPolicy();
this.uniqueNodesPropagationPolicy = new UniqueNodesYESPropagationPolicy();
}