docs: def get_manifest(self, asset_xml):
          """
          Construct and return the xml manifest to deliver along with video file.
          """
          # pylint: disable=E1101
          manifest = '<?xml version="1.0" encoding="utf-8"?>'
          manifest += '<publisher-upload-manifest publisher-id="%s" ' % \
              self.publisher_id
          manifest += 'preparer="%s" ' % self.preparer
          if self.report_success:
              manifest += 'report-success="TRUE">\n'
          for notify in self.notifications:
              manifest += '<notify email="%s"/>' % notify
          if self.callback:
              manifest += '<callback entity-url="%s"/>' % self.callback
          manifest += asset_xml
          manifest += '</publisher-upload-manifest>'
          return manifest