diff --git a/pika/adapters/base_connection.py b/pika/adapters/base_connection.py
index 37366c634f19a8fce6d65c3f5da5ca298349e550_cGlrYS9hZGFwdGVycy9iYXNlX2Nvbm5lY3Rpb24ucHk=..563618f55e81354826b97a921a31d0f7ce56a2b2_cGlrYS9hZGFwdGVycy9iYXNlX2Nvbm5lY3Rpb24ucHk= 100644
--- a/pika/adapters/base_connection.py
+++ b/pika/adapters/base_connection.py
@@ -57,7 +57,7 @@
         """
         if parameters and not isinstance(parameters, connection.Parameters):
             raise ValueError(
-                'Expected instance of Parameters, not %r' % parameters)
+                'Expected instance of Parameters, not %r' % (parameters,))
 
         # Let the developer know we could not import SSL
         if parameters and parameters.ssl and not ssl: