--- a/rust/hg-cpython/src/exceptions.rs	Thu Aug 10 11:01:07 2023 +0200
+++ b/rust/hg-cpython/src/exceptions.rs	Fri Aug 18 14:34:29 2023 +0200
@@ -18,13 +18,15 @@
 };
 use hg;
 
+use crate::PyRevision;
+
 py_exception!(rustext, GraphError, ValueError);
 
 impl GraphError {
     pub fn pynew(py: Python, inner: hg::GraphError) -> PyErr {
         match inner {
             hg::GraphError::ParentOutOfRange(r) => {
-                GraphError::new(py, ("ParentOutOfRange", r))
+                GraphError::new(py, ("ParentOutOfRange", PyRevision(r.0)))
             }
         }
     }