Traceback (most recent call last):


 "/usr/lib/python3.5/asyncio/base_events.py", line 431, in __del__


 "/usr/lib/python3.5/asyncio/unix_events.py", line 58, in close


 "/usr/lib/python3.5/asyncio/unix_events.py", line 139, in remove_signal_handler


 "/usr/lib/python3.5/signal.py", line 47, in signal
TypeError: signal handler must be signal.SIG_IGN, signal.SIG_DFL, or a callable object

Traceback (most recent call last):


 "/opt/jupyterhub/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 3254, in run_ast_nodes

if (await self.run_code(code, result,
async_=asy)):


 "/opt/jupyterhub/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 3348, in run_code

self.showtraceback(running_compiled_code=True)


 "/opt/jupyterhub/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2047, in showtraceback

value, tb, tb_offset=tb_offset)


 "/opt/jupyterhub/lib/python3.6/site-packages/IPython/core/ultratb.py", line 1418, in structured_traceback

self, etype, value, tb, tb_offset, number_of_lines_of_context)


 "/opt/jupyterhub/lib/python3.6/site-packages/IPython/core/ultratb.py", line 1318, in structured_traceback

self, etype, value, tb, tb_offset, number_of_lines_of_context


 "/opt/jupyterhub/lib/python3.6/site-packages/IPython/core/ultratb.py", line 1186, in structured_traceback

formatted_exceptions += self.prepare_chained_exception_message(evalue.__cause__)
TypeError: must be str, not list
