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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 _model_source_dir(self):
 """Get the appropriate value to pass as source_dir to model constructor on deploying Returns: str: Either a local or an S3 path pointing to the source_dir to be used for code by the model to be deployed """

        return self.source_dir if self.sagemaker_session.local_mode else self.uploaded_code.s3_prefix