/opt/conda/lib/python3.8/site-packages/prompt_toolkit/shortcuts/prompt.py in prompt(self, message, editing_mode, refresh_interval, vi_mode, lexer, completer, complete_in_thread, is_password, key_bindings, bottom_toolbar, style, color_depth, include_default_pygments_style, style_transformation, swap_light_and_dark_colors, rprompt, multiline, prompt_continuation, wrap_lines, enable_history_search, search_ignore_case, complete_while_typing, validate_while_typing, complete_style, auto_suggest, validator, clipboard, mouse_support, input_processors, reserve_space_for_menu, enable_system_prompt, enable_suspend, enable_open_in_editor, tempfile_suffix, tempfile, default, accept_default, pre_run, set_exception_handler)
    992             return get_event_loop().run_until_complete(self._dumb_prompt(self.message))
    993 
--> 994         return self.app.run(set_exception_handler=set_exception_handler)
    995 
    996     async def _dumb_prompt(self, message: AnyFormattedText = "") -> _T:

/opt/conda/lib/python3.8/site-packages/prompt_toolkit/application/application.py in run(self, pre_run, set_exception_handler)
    809             set_event_loop(loop)
    810 
--> 811         return loop.run_until_complete(
    812             self.run_async(pre_run=pre_run, set_exception_handler=set_exception_handler)
    813         )

/opt/conda/lib/python3.8/asyncio/base_events.py in run_until_complete(self, future)
    614             raise RuntimeError('Event loop stopped before Future completed.')
    615 
--> 616         return future.result()
    617 
    618     def stop(self):

/opt/conda/lib/python3.8/site-packages/prompt_toolkit/application/application.py in run_async(self, pre_run, set_exception_handler)
    776                     loop.set_exception_handler(previous_exc_handler)
    777 
--> 778         return await _run_async2()
    779 
    780     def run(

/opt/conda/lib/python3.8/site-packages/prompt_toolkit/application/application.py in _run_async2()
    764                         # `KeyboardInterrupt`, we still want to wait for the
    765                         # background tasks.
--> 766                         await self.cancel_and_wait_for_background_tasks()
    767 
    768                         # Set the `_is_running` flag to `False`. Normally this

/opt/conda/lib/python3.8/site-packages/prompt_toolkit/application/application.py in cancel_and_wait_for_background_tasks(self)
    865         for task in self.background_tasks:
    866             try:
--> 867                 await task
    868             except CancelledError:
    869                 pass

/opt/conda/lib/python3.8/site-packages/prompt_toolkit/buffer.py in new_coroutine(*a, **kw)
   1852             while True:
   1853                 try:
-> 1854                     await coroutine(*a, **kw)
   1855                 except _Retry:
   1856                     continue

/opt/conda/lib/python3.8/site-packages/prompt_toolkit/buffer.py in async_completer(select_first, select_last, insert_common_part, complete_event)
   1681                 return self.complete_state == complete_state
   1682 
-> 1683             async for completion in self.completer.get_completions_async(
   1684                 document, complete_event
   1685             ):

/opt/conda/lib/python3.8/site-packages/prompt_toolkit/completion/base.py in get_completions_async(self, document, complete_event)
    267         completer = self.get_completer() or DummyCompleter()
    268 
--> 269         async for completion in completer.get_completions_async(
    270             document, complete_event
    271         ):

/opt/conda/lib/python3.8/site-packages/prompt_toolkit/completion/base.py in get_completions_async(self, document, complete_event)
    194         Asynchronous generator of :class:`.Completion` objects.
    195         """
--> 196         for item in self.get_completions(document, complete_event):
    197             yield item
    198 

/opt/conda/lib/python3.8/site-packages/IPython/terminal/ptutils.py in get_completions(self, document, complete_event)
    114             except Exception as e:
    115                 from traceback import print_tb
--> 116                 print_tb(e)
    117 
    118     @staticmethod

/opt/conda/lib/python3.8/traceback.py in print_tb(tb, limit, file)
     51     method.
     52     """
---> 53     print_list(extract_tb(tb, limit=limit), file=file)
     54 
     55 def format_tb(tb, limit=None):

/opt/conda/lib/python3.8/traceback.py in extract_tb(tb, limit)
     70     whitespace stripped; if the source is not available it is None.
     71     """
---> 72     return StackSummary.extract(walk_tb(tb), limit=limit)
     73 
     74 #

/opt/conda/lib/python3.8/traceback.py in extract(klass, frame_gen, limit, lookup_lines, capture_locals)
    345         result = klass()
    346         fnames = set()
--> 347         for f, lineno in frame_gen:
    348             co = f.f_code
    349             filename = co.co_filename

/opt/conda/lib/python3.8/traceback.py in walk_tb(tb)
    310     """
    311     while tb is not None:
--> 312         yield tb.tb_frame, tb.tb_lineno
    313         tb = tb.tb_next
    314 

AttributeError: 'KeyError' object has no attribute 'tb_frame'

This is a bug caused by IPython:

/opt/conda/lib/python3.8/site-packages/IPython/terminal/ptutils.py in get_completions(self, document, complete_event)
    114             except Exception as e:
    115                 from traceback import print_tb
--> 116                 print_tb(e)
    117 
    118     @staticmethod


######################################################################
# Simulation investigation for above KeyError:
In [3]: def fun():
   ...:     try:
   ...:         s = {}
   ...:         k = s['0']
   ...:     except Exception as e:
   ...:         import sys
   ...:         from traceback import print_tb
   ...:         exc_type, exc_value, exc_traceback = sys.exc_info()
   ...:         print_tb(exc_traceback)
   ...: 

In [4]: fun()
  File "<ipython-input-3-d3df30294ed8>", line 4, in fun
    k = s['0']