diff --git a/rust/hg-cpython/src/cindex.rs b/rust/hg-cpython/src/cindex.rs
--- a/rust/hg-cpython/src/cindex.rs
+++ b/rust/hg-cpython/src/cindex.rs
@@ -68,6 +68,11 @@
             parents: get_parents_capi::retrieve(py)?,
         })
     }
+
+    /// return a reference to the CPython Index object in this Struct
+    pub fn inner(&self) -> &PyObject {
+        &self.index
+    }
 }
 
 impl Clone for Index {