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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 file_upload_to(self, instance, filename):
 """ Callable passed to the FileField's upload_to kwarg on Document.file """

        ext = filename.split(".")[-1]
        filename = "{}.{}".format(uuid.uuid4(), ext)
        return os.path.join("document", filename)