diff --git a/n2vc/exceptions.py b/n2vc/exceptions.py
index 4b83e3f..c8e8793 100644
--- a/n2vc/exceptions.py
+++ b/n2vc/exceptions.py
@@ -40,6 +40,10 @@
     """The authentication for the specified user failed."""
 
 
+class NotImplemented(Exception):
+    """The method is not implemented."""
+
+
 class N2VCException(Exception):
     """
     N2VC exception base class
@@ -107,6 +111,7 @@
     def __str__(self):
         return '<{}> Error executing primitive {} failed: {}'.format(type(self), self.primitive_name, super().__str__())
 
+
 class N2VCInvalidCertificate(N2VCException):
     """
     Invalid certificate