Unhandled exception when creating csv reader

[Almenon]

import csv

with open('stocks.csv') as f:
  x = csv.reader(f)

Traceback (most recent call last):\n File "C:\dev\AREPL\src\python\pythonEvaluator.py", line 53, in exec_input\n returnInfo['userVariables'] = jsonpickle.encode(userVariables)\n File "C:\dev\AREPL\src\python\jsonpickle_init_.py", line 135, in encode\n numeric_keys=numeric_keys)\n File "C:\dev\AREPL\src\python\jsonpickle\pickler.py", line 44, in encode\n return backend.encode(context.flatten(value, reset=reset))\n File "C:\dev\AREPL\src\python\jsonpickle\pickler.py", line 157, in flatten\n return self._flatten(obj)\n File "C:\dev\AREPL\src\python\jsonpickle\pickler.py", line 161, in _flatten\n return self._pop(self._flatten_obj(obj))\n File "C:\dev\AREPL\src\python\jsonpickle\pickler.py", line 177, in _flatten_obj\n return flatten_func(obj)\n File "C:\dev\AREPL\src\python\jsonpickle\pickler.py", line 429, in _flatten_dict_obj\n flatten(k, v, data)\n File "C:\dev\AREPL\src\python\jsonpickle\pickler.py", line 498, in _flatten_key_value_pair\n data[k] = self._flatten(v)\n File "C:\dev\AREPL\src\python\jsonpickle\pickler.py", line 161, in _flatten\n return self._pop(self._flatten_obj(obj))\n File "C:\dev\AREPL\src\python\jsonpickle\pickler.py", line 177, in _flatten_obj\n return flatten_func(obj)\n File "C:\dev\AREPL\src\python\jsonpickle\pickler.py", line 235, in _ref_obj_instance\n return self._flatten_obj_instance(obj)\n File "C:\dev\AREPL\src\python\jsonpickle\pickler.py", line 367, in _flatten_obj_instance\n data[tags.ITERATOR] = list(map(self._flatten, islice(obj, self._max_iter)))\nValueError: I/O operation on closed file.\n

It looks like JSONpickle is failing to encode x. The JSONpickle API mentions that it can't encode file descriptors so this might be related to that. Still, I would've expected x to be encoded as None rather than an unhandled exception.