Add hook to base register to control task class attributes.

Author: riga

law/task/base.py

@@ -68,6 +68,9 @@ def __new__(metacls, classname, bases, classdict):
         if cls.update_register:
             cls.deregister()
 
+        # invoke the class-level attribute update hook
+        cls.update_task_attributes()
+
         # add to register (mimic luigi.task_register.Register.__new__)
         cls._namespace_at_class_time = metacls._get_namespace(cls.__module__)
         metacls._reg.append(cls)
@@ -120,6 +123,13 @@ def deregister(cls, task_cls=None):
 
         return success
 
+    @classmethod
+    def update_task_attributes(cls):
+        """
+        Hook to update class attributes before the class is added to the register.
+        """
+        return
+
     @classmethod
     def modify_param_args(cls, params, args, kwargs):
         """