UpdateGroup.
        [Preview API] Update the properties of a VSTS group.
        :param str group_descriptor: The descriptor of the group to modify.
        :param :class:`<[JsonPatchOperation]> <azure.devops.v5_0.graph.models.[JsonPatchOperation]>` patch_document: The JSON+Patch document containing the fields to alter.
        :rtype: :class:`<GraphGroup> <azure.devops.v5_0.graph.models.GraphGroup>`

def update_group(self, group_descriptor, patch_document):
        """UpdateGroup.
        [Preview API] Update the properties of a VSTS group.
        :param str group_descriptor: The descriptor of the group to modify.
        :param :class:`<[JsonPatchOperation]> <azure.devops.v5_0.graph.models.[JsonPatchOperation]>` patch_document: The JSON+Patch document containing the fields to alter.
        :rtype: :class:`<GraphGroup> <azure.devops.v5_0.graph.models.GraphGroup>`
        """
        route_values = {}
        if group_descriptor is not None:
            route_values['groupDescriptor'] = self._serialize.url('group_descriptor', group_descriptor, 'str')
        content = self._serialize.body(patch_document, '[JsonPatchOperation]')
        response = self._send(http_method='PATCH',
                              location_id='ebbe6af8-0b91-4c13-8cf1-777c14858188',
                              version='5.0-preview.1',
                              route_values=route_values,
                              content=content,
                              media_type='application/json-patch+json')
        return self._deserialize('GraphGroup', response)