Backends: Removed is_successful(), replaced by AsyncResult.success().

celery/backends/base.py

@@ -67,10 +67,6 @@ class BaseBackend(object):
         """Prepare value for storage."""
         return result
 
-    def is_successful(self, task_id):
-        """Returns ``True`` if the task was successfully executed."""
-        return self.get_status(task_id) == states.SUCCESS
-
     def wait_for(self, task_id, timeout=None):
         """Wait for task and return its result.
 

celery/result.py

@@ -84,7 +84,7 @@ class BaseAsyncResult(object):
         :rtype: bool
 
         """
-        return self.backend.is_successful(self.task_id)
+        return self.backend.get_status(self.task_id) == states.SUCCESS
 
     def __str__(self):
         """``str(self)`` -> ``self.task_id``"""