<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def complete_upload(self):
 """ Complete the MultiPart Upload operation. This method should be called when all parts of the file have been successfully uploaded to S3. :rtype: :class:`boto.s3.multipart.CompletedMultiPartUpload` :returns: An object representing the completed upload. """

        xml = self.to_xml()
        return self.bucket.complete_multipart_upload(self.key_name,
                                                     self.id, xml)