def push_pos(self, *args):
        """Set my current position, expressed as proportions of the board's
        width and height, into the ``_x`` and ``_y`` keys of the
        entity in my ``proxy`` property, such that it will be
        recorded in the database.

        """
        self.proxy['_x'] = self.x / self.board.width
        self.proxy['_y'] = self.y / self.board.height
Set my current position, expressed as proportions of the board's
        width and height, into the ``_x`` and ``_y`` keys of the
        entity in my ``proxy`` property, such that it will be
        recorded in the database.