code: def maintainer(self):
          
          maintainer = namedtuple('Maintainer', 'name email')
          return maintainer(name=self._package['maintainer'],
                            email=self._package['maintainer_email'])
docs: >>> package = yarg.get('yarg')
              >>> package.maintainer
              Maintainer(name=u'Kura', email=u'kura@kura.io')