In [5]: data_results = Parallel(n_jobs=4)(delayed(a)() for i in range(10))
--------------------------------------------------------------------------- 
_RemoteTraceback                          Traceback (most recent call last)
_RemoteTraceback:
"""
Traceback (most recent call last):
  File "C:\Python\lib\site-packages\joblib\externals\loky\process_executor.py", line 428, in _process_worker
    r = call_item()
  File "C:\Python\lib\site-packages\joblib\externals\loky\process_executor.py", line 275, in __call__
    return self.fn(*self.args, **self.kwargs)
  File "C:\Python\lib\site-packages\joblib\_parallel_backends.py", line 620, in __call__
    return self.func(*args, **kwargs)
  File "C:\Python\lib\site-packages\joblib\parallel.py", line 288, in __call__
    return [func(*args, **kwargs)
  File "C:\Python\lib\site-packages\joblib\parallel.py", line 288, in <listcomp>
    return [func(*args, **kwargs)
  File "<ipython-input-1-bf041901e974>", line 2, in a
  File "C:\Python\lib\site-packages\sklearn\model_selection\__init__.py", line 23, in <module>
    from ._validation import cross_val_score
  File "C:\Python\lib\site-packages\sklearn\model_selection\_validation.py", line 32, in <module>
    from ..metrics import check_scoring
  File "C:\Python\lib\site-packages\sklearn\metrics\__init__.py", line 41, in <module>
    from . import cluster
  File "C:\Python\lib\site-packages\sklearn\metrics\cluster\__init__.py", line 22, in <module>
    from ._unsupervised import silhouette_samples
  File "C:\Python\lib\site-packages\sklearn\metrics\cluster\_unsupervised.py", line 16, in <module>
    from ..pairwise import pairwise_distances_chunked
  File "C:\Python\lib\site-packages\sklearn\metrics\pairwise.py", line 33, in <module>
    from ._pairwise_distances_reduction import PairwiseDistancesArgKmin
ImportError: DLL load failed while importing _pairwise_distances_reduction: The specified module could not be found.
"""

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

ImportError                               Traceback (most recent call last)
Cell In [5], line 1
----> 1 data_results = Parallel(n_jobs=4)(delayed(a)() for i in range(10))

File C:\Python\lib\site-packages\joblib\parallel.py:1098, in Parallel.__call__(self, iterable)
   1095     self._iterating = False
   1097 with self._backend.retrieval_context():
-> 1098     self.retrieve() 
   1099 # Make sure that we get a last message telling us we are done
   1100 elapsed_time = time.time() - self._start_time

File C:\Python\lib\site-packages\joblib\parallel.py:975, in Parallel.retrieve(self)
    973 try:
    974     if getattr(self._backend, 'supports_timeout', False):
--> 975         self._output.extend(job.get(timeout=self.timeout))
    976     else:
    977         self._output.extend(job.get())
 
File C:\Python\lib\site-packages\joblib\_parallel_backends.py:567, in LokyBackend.wrap_future_result(future, timeout)
    564 """Wrapper for Future.result to implement the same behaviour as
    565 AsyncResults.get from multiprocessing."""
    566 try:
--> 567     return future.result(timeout=timeout)
    568 except CfTimeoutError as e:
    569     raise TimeoutError from e
 
File C:\Python\lib\concurrent\futures\_base.py:458, in Future.result(self, timeout)
    456     raise CancelledError()
    457 elif self._state == FINISHED:
--> 458     return self.__get_result()
    459 else:
    460     raise TimeoutError()
 
File C:\Python\lib\concurrent\futures\_base.py:403, in Future.__get_result(self)
    401 if self._exception:
    402     try:
--> 403         raise self._exception
    404     finally:
    405         # Break a reference cycle with the exception in self._exception
    406         self = None

ImportError: DLL load failed while importing _pairwise_distances_reduction: The specified module could not be found.