diff --git a/Python/ceval.c b/Python/ceval.c
index 131f5a7..c371f28 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -3905,7 +3905,7 @@
 			}
 		} else {
 			PyErr_SetString(PyExc_TypeError,
-					"slice indices must be integers");
+					"slice indices must be integers or None");
 			return 0;
 		}
 		*pi = x;