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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 smart_content_type(self):
 """Smart content type."""

        content_type = self.content_type
        if content_type in (None, '', 'application/octet-stream'):
            content_type, _ = mimetypes.guess_type(self.name)

        return content_type