public ActionResult DeleteExpert(Guid expertId)
        {
            if (!expertRepository.ExpertExist(expertId))
            {
                return(NotFound());
            }

            if (expertRepository
                .GetExpertIncludedProjectsAndRoles(expertId)
                .ExpertProjects.Count > 0)
            {
                expertRepository.RemoveProjectsFromExpert(expertId);
            }

            expertRepository.DeleteExpert(expertId);
            expertRepository.Save();
            return(NoContent());
        }