def yield_all_rects(self):
        """Yield rects from all objects in the graph.

        Calling it when the graph is empty will raise an error.

        This is used by a rectsman instance that can manage the
        position of all rects in the graph and grab related information.

        A rectsman is an instance of the RectsManager class, that
        can be used to control the position of multiple rects and
        obtain data about them.

        A rectsman can be created by feeding this method to its
        constructor.
        """
        ### rects (rectsmans) from nodes
        for node in self.nodes:
            yield node.rectsman

        ### rects from preview toolbars

        for toolbar in self.preview_toolbars:
            yield toolbar.rect

        ### rects from preview panels

        for panel in self.preview_panels:
            yield panel.rect

        ### rects from text blocks

        for block in self.text_blocks:
            yield block.rect
Yield rects from all objects in the graph.

        Calling it when the graph is empty will raise an error.

        This is used by a rectsman instance that can manage the
        position of all rects in the graph and grab related information.

        A rectsman is an instance of the RectsManager class, that
        can be used to control the position of multiple rects and
        obtain data about them.

        A rectsman can be created by feeding this method to its
        constructor.
        
nodezator/graphman/main.py