Traverse master class hierarchy to collect all defined labels

i.e. for forms and grids

tailbone/views/master.py

@@ -193,13 +193,50 @@ class MasterView(View):
         return getattr(cls, 'mobile_row_grid_factory', grids.MobileGrid)
 
     def set_labels(self, obj):
-        for key, label in self.labels.items():
+        labels = self.collect_labels()
+        for key, label in six.iteritems(labels):
             obj.set_label(key, label)
 
+    def collect_labels(self):
+        """
+        Collect all labels defined within the master class hierarchy.
+        """
+        labels = {}
+        hierarchy = self.get_class_hierarchy()
+        for cls in hierarchy:
+            if hasattr(cls, 'labels'):
+                labels.update(cls.labels)
+        return labels
+
+    def get_class_hierarchy(self):
+        hierarchy = []
+
+        def traverse(cls):
+            if cls is not object:
+                hierarchy.append(cls)
+                for parent in cls.__bases__:
+                    traverse(parent)
+
+        traverse(self.__class__)
+        hierarchy.reverse()
+        return hierarchy
+
     def set_row_labels(self, obj):
-        for key, label in self.row_labels.items():
+        labels = self.collect_row_labels()
+        for key, label in six.iteritems(labels):
             obj.set_label(key, label)
 
+    def collect_row_labels(self):
+        """
+        Collect all row labels defined within the master class hierarchy.
+        """
+        labels = {}
+        hierarchy = self.get_class_hierarchy()
+        for cls in hierarchy:
+            if hasattr(cls, 'row_labels'):
+                labels.update(cls.row_labels)
+        return labels
+
     ##############################
     # Available Views
     ##############################