private async Task <List <Separation> > GetSeparationsByIds(ICollection <Separation> separations)
        {
            var separationsIds = Separations
                                 .Select(x => x.SeparationId)
                                 .ToList();

            return(await Separations
                   .Where(x => separationsIds.Contains(x.SeparationId))
                   .ToListAsync());
        }
        public async ValueTask <bool> AddNewDoctorAsync(int separationId, Doctor doctor)
        {
            try
            {
                var sep = await Separations
                          .Where(s => s.SeparationId == separationId)
                          .FirstOrDefaultAsync();

                if (sep == null)
                {
                    return(false);
                }

                sep.DoctorList.Add(doctor);

                await SaveChangesAsync();
            }
            catch
            {
                return(false);
            }

            return(true);
        }