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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def download(self):
 """Start a celery task to download the release file from pypi. If `settings.LOCALSHOP_ISOLATED` is True then download the file in-process. """

        from .tasks import download_file
        if not settings.LOCALSHOP_ISOLATED:
            download_file.delay(pk=self.pk)
        else:
            download_file(pk=self.pk)