code: def get_group(self, group_descriptor):
          
          route_values = {}
          if group_descriptor is not None:
              route_values['groupDescriptor'] = self._serialize.url('group_descriptor', group_descriptor, 'str')
          response = self._send(http_method='GET',
                                location_id='ebbe6af8-0b91-4c13-8cf1-777c14858188',
                                version='5.0-preview.1',
                                route_values=route_values)
          return self._deserialize('GraphGroup', response)
docs: GetGroup.
          [Preview API] Get a group by its descriptor.
          :param str group_descriptor: The descriptor of the desired graph group.
          :rtype: :class:`<GraphGroup> <azure.devops.v5_0.graph.models.GraphGroup>`