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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 get_writable_metadata(self, file_format):
 """ Convert the metadata to a writable form. :param file_format: the needed format can be json or xml :type file_format: str :return: the dupled metadata :rtype: str """

        if file_format == 'json':
            metadata = self.json
        elif file_format == 'xml':
            metadata = self.xml
        else:
            raise TypeError('The requested file type (%s) is not yet supported'
                            % file_format)
        return metadata