namespac share namespac object ns object ns ns ns illeg argument except argument ns namespac illeg argument except expect namespac argument got ns ns namespac illeg argument except expect namespac argument got ns ns ns namespac ns namespac hierarchi element iter namespac path path namespac ns iter iter namespac path path namespac ns iter travers list look innermost match namespac match path path namespac element path element path match match element match invalid object except invalid element except 