Part: [skip ci] allow to create empty shapes of each type

src/Mod/Part/App/TopoShapeFacePyImp.cpp

@@ -117,6 +117,13 @@ PyObject *TopoShapeFacePy::PyMake(struct _typeobject *, PyObject *, PyObject *)
 // constructor method
 int TopoShapeFacePy::PyInit(PyObject* args, PyObject* /*kwd*/)
 {
+    if (PyArg_ParseTuple(args, "")) {
+        // Undefined Face
+        getTopoShapePtr()->setShape(TopoDS_Face());
+        return 0;
+    }
+
+    PyErr_Clear();
     PyObject *pW;
     if (PyArg_ParseTuple(args, "O!", &(Part::TopoShapePy::Type), &pW)) {
         try {