Segmentation fault when using .source() method of QDropEvent

When the .source() method is called on a QDropEvent, for a drag-and-drop that originated with another Qt widget, there is a segmentation fault. This happens in the attached example if you type text into QTextEdit widget, and then try to drag the text within the QTextEdit widget. The segmentation fault does not occur if the line "print(str(event.source()))" is commented out. When the line is not commented out, it appears that the statement executes successfully (the appropriate output is sent to stdout) but a segmentation fault happens shortly thereafter.