rm node visitor

Base/Py/PyUtils.cpp

@@ -24,9 +24,11 @@
 std::string BaseUtils::Python::toString(PyObject* obj)
 {
     std::string result;
-    PyObject* pyStr = PyUnicode_AsEncodedString(obj, "utf-8", "Error ~");
-    result = std::string(PyBytes_AsString(pyStr));
-    Py_DecRef(pyStr);
+    PyObject* pyStr = PyUnicode_AsEncodedString(obj, "utf-8", "replace");
+    if (pyStr != nullptr) {
+        result = std::string(PyBytes_AsString(pyStr));
+        Py_DecRef(pyStr);
+    }
     return result;
 }