[Exp PyROOT] Fall back to __repr__ in __str__ if cling returns an address

bindings/pyroot_experimental/PyROOT/src/GenericPyz.cxx

@@ -27,7 +27,13 @@ PyObject *ClingPrintValue(CPPInstance *self)
 {
    const std::string className = GetCppName(self);
    auto printResult = gInterpreter->ToString(className.c_str(), self->GetObject());
-   return CPyCppyy_PyUnicode_FromString(printResult.c_str());
+   if (printResult.find("@0x") == 0) {
+      // Fall back to __repr__ if we just get an address from cling
+      auto method = PyObject_GetAttrString((PyObject*)self, "__repr__");
+      return PyObject_CallObject(method, nullptr);
+   } else {
+      return CPyCppyy_PyUnicode_FromString(printResult.c_str());
+   }
 }
 
 ////////////////////////////////////////////////////////////////////////////