How do I fix (raise ValueError("Duplicate Signature: %r" % signature) when I try to run the parallel_apply function from pandarallel

Question

Hi I am getting a error (raise ValueError("Duplicate Signature: %r" % signature) when I try to run the parallel_apply function from pandarallel.

I am using spyder from Anaconda to run the code, there is no issues with the code, the error appears only whenever I try using the parallel_apply function. How do I fix this?

score 1 · Answer 1 · answered Aug 11 '21 at 15:32

This looks to be a bug in Jupyter where the messages from forked processes using libraries like multiprocessing can be duplicated, and they are then rejected, resulting in that exception.

This patch fixes it by changing the client messages to be unique for each fork. Note that it's not in jupyter_client yet (as of my writing this), but it's a one-liner so you can probably just apply it to your local install. Once 7.0 is out, it should be included.

How do I fix (raise ValueError("Duplicate Signature: %r" % signature) when I try to run the parallel_apply function from pandarallel

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