diff --git a/error.py b/error.py
index 2148248..7e52b01 100644
--- a/error.py
+++ b/error.py
@@ -21,6 +21,10 @@
   """The revision value in a project is incorrect.
   """
 
+class NoManifestException(Exception):
+  """The required manifest does not exist.
+  """
+
 class EditorError(Exception):
   """Unspecified error from the user's text editor.
   """