Getthe GIL before raisign an exception

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@29213 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

wxPython/src/_image.i

@@ -200,7 +200,8 @@ nothing.", "");
             unsigned char* dataPtr;
 
             if (! PyString_Check(data)) {
-                PyErr_SetString(PyExc_TypeError, "Expected string object");
+                wxPyBLOCK_THREADS(PyErr_SetString(PyExc_TypeError,
+                                                  "Expected string object"));
                 return /* NULL */ ;
             }