Avoid double initialization of the backend class that Python can do w…

…hen using an empty string in the from list.

notification/backends/__init__.py

@@ -1,4 +1,6 @@
 
+import sys
+
 from django.conf import settings
 from django.core import exceptions
 
@@ -7,13 +9,15 @@
 def load_backends():
     backends = []
     for label, backend_path in getattr(settings, "NOTIFICATION_BACKENDS", tuple()):
-        dot = backend_path.rindex('.')
+        dot = backend_path.rindex(".")
         backend_mod, backend_class = backend_path[:dot], backend_path[dot+1:]
         try:
-            mod = __import__(backend_mod, {}, {}, [""])
+            # import the module and get the module from sys.modules
+            __import__(backend_mod)
+            mod = sys.modules[backend_mod]
         except ImportError, e:
             raise exceptions.ImproperlyConfigured, 'Error importing notification backend %s: "%s"' % (backend_mod, e)
         # add the backend label and an instantiated backend class to the
         # backends list.
-        backends.append(label, getattr(backend_mod, "")())
+        backends.append(label, getattr(backend_mod, backend_class)())
     return dict(backend_list)