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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 pull(self, platform=None):
 """ Pull the image digest. Args: platform (str):
 The platform to pull the image for. Default: ``None`` Returns: (:py:class:`Image`):
 A reference to the pulled image. """

        repository, _ = parse_repository_tag(self.image_name)
        return self.collection.pull(repository, tag=self.id, platform=platform)