using in_typemapper instead of self.typemapper.keys for looking up resource_uri's now

piston/emitters.py

@@ -185,8 +185,8 @@ class Emitter(object):
                     ret[k] = _any(getattr(data, k))
             
             # resouce uri
-            if type(data) in self.typemapper.keys():
-                handler = self.typemapper.get(type(data))
+            if self.in_typemapper(type(data), self.anonymous):
+                handler = self.in_typemapper(type(data), self.anonymous)
                 if hasattr(handler, 'resource_uri'):
                     url_id, fields = handler.resource_uri()
                     ret['resource_uri'] = permalink( lambda: (url_id,