diff --git a/Libs/swig/VisusPy.common b/Libs/swig/VisusPy.common
index b8cb90cf..ef1c98b3 100644
--- a/Libs/swig/VisusPy.common
+++ b/Libs/swig/VisusPy.common
@@ -54,13 +54,13 @@ For support : support@visus.net
 
 #include <Visus/Kernel.h>
 
+
 static String convertToString(PyObject* value)
 {
     if (!value) return "";
     PyObject* py_str = PyObject_Str(value);
-    auto tmp = SWIG_Python_str_AsChar(py_str);
+    const char* tmp = py_str? PyUnicode_AsUTF8(py_str) : nullptr; //cit "The caller is not responsible for deallocating the buffer."
     String ret = tmp ? tmp : "";
-    SWIG_Python_str_DelForPy3(tmp);
     Py_DECREF(py_str);
     return ret;
 }