---------------------------------------------------------------------------
_RemoteTraceback                          Traceback (most recent call last)
_RemoteTraceback: 
"""
Traceback (most recent call last):
  File "/home/bas.nijholt/micromamba/envs/pipefunc/lib/python3.12/concurrent/futures/process.py", line 263, in _process_worker
    r = call_item.fn(*call_item.args, **call_item.kwargs)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/bas.nijholt/micromamba/envs/pipefunc/lib/python3.12/concurrent/futures/process.py", line 212, in _process_chunk
    return [fn(*args) for args in chunk]
            ^^^^^^^^^
  File "/home/bas.nijholt/repos/pipefunc/pipefunc/_pipeline.py", line 1304, in call_with_dict
    return self(**kwargs)
           ^^^^^^^^^^^^^^
  File "/home/bas.nijholt/repos/pipefunc/pipefunc/_pipeline.py", line 1274, in __call__
    return self.pipeline.run(output_name=self.output_name, kwargs=kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/bas.nijholt/repos/pipefunc/pipefunc/_pipeline.py", line 490, in run
    self._run(
  File "/home/bas.nijholt/repos/pipefunc/pipefunc/_pipeline.py", line 422, in _run
    return_now, result_from_cache = _get_result_from_cache(
                                    ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/bas.nijholt/repos/pipefunc/pipefunc/_pipeline.py", line 1398, in _get_result_from_cache
    if cache_key is not None and cache_key in cache:
                                 ^^^^^^^^^^^^^^^^^^
  File "/home/bas.nijholt/repos/pipefunc/pipefunc/_cache.py", line 316, in __contains__
    return key in self._cache_dict
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "<string>", line 2, in __contains__
  File "/home/bas.nijholt/micromamba/envs/pipefunc/lib/python3.12/multiprocessing/managers.py", line 820, in _callmethod
    conn.send((self._id, methodname, args, kwds))
  File "/home/bas.nijholt/micromamba/envs/pipefunc/lib/python3.12/multiprocessing/connection.py", line 206, in send
    self._send_bytes(_ForkingPickler.dumps(obj))
  File "/home/bas.nijholt/micromamba/envs/pipefunc/lib/python3.12/multiprocessing/connection.py", line 427, in _send_bytes
    self._send(header + buf)
  File "/home/bas.nijholt/micromamba/envs/pipefunc/lib/python3.12/multiprocessing/connection.py", line 384, in _send
    n = write(self._handle, buf)
        ^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: 'NoneType' object cannot be interpreted as an integer
"""

The above exception was the direct cause of the following exception:

TypeError                                 Traceback (most recent call last)
Cell In[1], line 19
     17 with ProcessPoolExecutor(max_workers=1) as executor:
     18     results = executor.map(func.call_with_dict, sequence)
---> 19     list(results)

File ~/micromamba/envs/pipefunc/lib/python3.12/concurrent/futures/process.py:642, in _chain_from_iterable_of_lists(iterable)
    636 def _chain_from_iterable_of_lists(iterable):
    637     """
    638     Specialized implementation of itertools.chain.from_iterable.
    639     Each item in *iterable* should be a list.  This function is
    640     careful not to keep references to yielded objects.
    641     """
--> 642     for element in iterable:
    643         element.reverse()
    644         while element:

File ~/micromamba/envs/pipefunc/lib/python3.12/concurrent/futures/_base.py:619, in Executor.map.<locals>.result_iterator()
    616 while fs:
    617     # Careful not to keep a reference to the popped future
    618     if timeout is None:
--> 619         yield _result_or_cancel(fs.pop())
    620     else:
    621         yield _result_or_cancel(fs.pop(), end_time - time.monotonic())

File ~/micromamba/envs/pipefunc/lib/python3.12/concurrent/futures/_base.py:317, in _result_or_cancel(***failed resolving arguments***)
    315 try:
    316     try:
--> 317         return fut.result(timeout)
    318     finally:
    319         fut.cancel()

File ~/micromamba/envs/pipefunc/lib/python3.12/concurrent/futures/_base.py:456, in Future.result(self, timeout)
    454     raise CancelledError()
    455 elif self._state == FINISHED:
--> 456     return self.__get_result()
    457 else:
    458     raise TimeoutError()

File ~/micromamba/envs/pipefunc/lib/python3.12/concurrent/futures/_base.py:401, in Future.__get_result(self)
    399 if self._exception:
    400     try:
--> 401         raise self._exception
    402     finally:
    403         # Break a reference cycle with the exception in self._exception
    404         self = None

TypeError: 'NoneType' object cannot be interpreted as an integer