my_dict = {'Circle': {'Ellipse',           'Shape',           'ShapeDriver'},'Ellipse': {'Shape'},'Rectangle': {'Shape'},'Shape': {'Circle'},'ShapeDriver': {'Circle',                'Ellipse',                'Shape'},'Square': {'Rectangle'}}

~ % bpythonbpython version 0.21 on top of Python 3.8.2 /Library/Developer/CommandLineTools/usr/bin/python3>>> my_dict = {... 'a/Circle': {'Ellipse',...            'Shape',...            'ShapeDriver'},... ... 'a/Ellipse': {'Shape'},... ... 'a/Rectangle': {'Shape'},... ... 'a/Shape': {'Circle'},... ... 'a/ShapeDriver': {'Circle',...                 'Ellipse',...                 'Shape'},... ... 'a/Square': {'Rectangle'}... }>>> my_dict['b/banana']Traceback (most recent call last):  File "/Users/arian/Library/Python/3.8/bin/bpython", line 8, in <module>    sys.exit(main())  File "/Users/arian/Library/Python/3.8/lib/python/site-packages/bpython/curtsies.py", line 201, in main    exit_value = repl.mainloop(True, paste)  File "/Users/arian/Library/Python/3.8/lib/python/site-packages/bpython/curtsies.py", line 121, in mainloop    self.process_event_and_paint(e)  File "/Users/arian/Library/Python/3.8/lib/python/site-packages/bpython/curtsies.py", line 85, in process_event_and_paint    self.process_event(e)  File "/Users/arian/Library/Python/3.8/lib/python/site-packages/bpython/curtsiesfrontend/repl.py", line 615, in process_event    return self.process_key_event(e)  File "/Users/arian/Library/Python/3.8/lib/python/site-packages/bpython/curtsiesfrontend/repl.py", line 757, in process_key_event    self.on_tab()  File "/Users/arian/Library/Python/3.8/lib/python/site-packages/bpython/curtsiesfrontend/repl.py", line 891, in on_tab    cursor_and_line = self.matches_iter.substitute_cseq()  File "/Users/arian/Library/Python/3.8/lib/python/site-packages/bpython/repl.py", line 297, in substitute_cseq    self.update(  File "/Users/arian/Library/Python/3.8/lib/python/site-packages/bpython/repl.py", line 318, in update    self.start, self.end, self.current_word = self.completer.locate(TypeError: cannot unpack non-iterable NoneType object