Encountered "ValueError: I/O operation on closed file" in kernelbase.py

running jupyter notebook for a few hours and crashing in recent venv (few days old only). error message only retrievable from anaconda prompt. windows 10

`[IPKernelApp] ERROR | Error in message handler Traceback (most recent call last): File "H:\Anaconda3\envs\np\lib\site-packages\ipykernel\kernelbase.py", line 377, in dispatch_queue yield self.process_one() File "H:\Anaconda3\envs\np\lib\site-packages\tornado\gen.py", line 735, in run value = future.result() File "H:\Anaconda3\envs\np\lib\site-packages\tornado\gen.py", line 742, in run yielded = self.gen.throw(*exc_info) # type: ignore File "H:\Anaconda3\envs\np\lib\site-packages\ipykernel\kernelbase.py", line 361, in process_one yield gen.maybe_future(dispatch(*args)) File "H:\Anaconda3\envs\np\lib\site-packages\tornado\gen.py", line 735, in run value = future.result() File "H:\Anaconda3\envs\np\lib\site-packages\tornado\gen.py", line 742, in run yielded = self.gen.throw(*exc_info) # type: ignore File "H:\Anaconda3\envs\np\lib\site-packages\ipykernel\kernelbase.py", line 277, in dispatch_shell sys.stdout.flush() ValueError: I/O operation on closed file.`