@classmethod
def set_cursor(cls, widget, cursor_name='parent'):
    """ Set the cursor named cursor_name'.

        Args:
            widget (:class:`~Gtk.Widget`): The widget triggering the cursor change, used to retrieve a Gdk.Window
            cursor_name (`str`): Name of the cursor to be set
        """
    try:
        cursor = cls._cursors[cursor_name]
    except KeyError:
        cls._populate_cursors()
        cursor = cls._cursors[cursor_name]
    widget.get_window().set_cursor(cursor)
