def _cursor_up(self, value):
        """
        Moves the cursor up by ``value``.
        """
        value = int(value)
        if value == 0:
            value = 1
        self._cursor.clearSelection()
        self._cursor.movePosition(self._cursor.Up, self._cursor.MoveAnchor, value)
        self._last_cursor_pos = self._cursor.position()