Updates name and/or path of the specified group.

        :type group_name: string
        :param group_name: The name of the new group

        :type new_group_name: string
        :param new_group_name: If provided, the name of the group will be
                               changed to this name.

        :type new_path: string
        :param new_path: If provided, the path of the group will be
                         changed to this path.

def update_group(self, group_name, new_group_name=None, new_path=None):
        """
        Updates name and/or path of the specified group.

        :type group_name: string
        :param group_name: The name of the new group

        :type new_group_name: string
        :param new_group_name: If provided, the name of the group will be
                               changed to this name.

        :type new_path: string
        :param new_path: If provided, the path of the group will be
                         changed to this path.

        """
        params = {'GroupName' : group_name}
        if new_group_name:
            params['NewGroupName'] = new_group_name
        if new_path:
            params['NewPath'] = new_path
        return self.get_response('UpdateGroup', params)