diff --git a/src/calibre/devices/mtp/windows/content_enumeration.cpp b/src/calibre/devices/mtp/windows/content_enumeration.cpp
index 181bc8f71f..db2013925d 100644
--- a/src/calibre/devices/mtp/windows/content_enumeration.cpp
+++ b/src/calibre/devices/mtp/windows/content_enumeration.cpp
@@ -502,7 +502,7 @@ get_files_and_folders(unsigned int level, IPortableDevice *device, CComPtr<IPort
 	}
 
     for (Py_ssize_t i = 0; i < PyList_GET_SIZE(subfolders.ptr()); i++) {
-		wchar_raii child_id(PyList_GET_ITEM(subfolders.ptr(), i));
+		wchar_raii child_id(PyUnicode_AsWideCharString(PyList_GET_ITEM(subfolders.ptr(), i), NULL));
         if (!child_id) return false;
         if (!get_files_and_folders(level+1, device, content, bulk_properties, child_id.ptr(), callback, ans)) return false;
     }
diff --git a/src/calibre/utils/cpp_binding.h b/src/calibre/utils/cpp_binding.h
index afc9f684c2..d8ec8c31a8 100644
--- a/src/calibre/utils/cpp_binding.h
+++ b/src/calibre/utils/cpp_binding.h
@@ -41,15 +41,7 @@ class generic_raii {
 		explicit operator bool() const noexcept { return handle != null; }
 };
 
-class wchar_raii : public generic_raii<wchar_t*, PyMem_Free> {
-	public:
-		explicit wchar_raii() noexcept { handle = NULL; }
-		explicit wchar_raii(wchar_t *h) noexcept { handle = h; }
-		explicit wchar_raii(PyObject *unicode_object) noexcept {
-			if (!unicode_object || !PyUnicode_Check(unicode_object)) { handle = NULL; PyErr_SetString(PyExc_TypeError, "Not a unicode object"); }
-			else handle = PyUnicode_AsWideCharString(unicode_object, NULL);
-		}
-};
+typedef generic_raii<wchar_t*, PyMem_Free> wchar_raii;
 static inline void python_object_destructor(void *p) { PyObject *x = reinterpret_cast<PyObject*>(p); Py_XDECREF(x); }
 typedef generic_raii<PyObject*, python_object_destructor> pyobject_raii;