> ## Documentation Index > Fetch the complete documentation index at: https://docs.wandb.ai/llms.txt > Use this file to discover all available pages before exploring further. # Does W&B use the `multiprocessing` library? Yes, W\&B uses the `multiprocessing` library. As a result, scripts that call W\&B directly need to guard their entry point so that child processes don't re-run the top-level code. The following error message indicates this issue: ``` An attempt has been made to start a new process before the current process has finished its bootstrapping phase. ``` To resolve this error, add entry point protection with `if __name__ == "__main__":`. You need this protection when you run W\&B directly from the script. It ensures that worker processes spawned by `multiprocessing` don't re-run your training code. *** [Experiments](/support/models/tags/experiments)