public ResultCode AddSchoolWithDetails(school schoolOb) { school schoolDetails = new school { Address = schoolOb.Address, Name = schoolOb.Name }; List <Teacher> teachers = new List <Teacher>(); if (schoolOb.Teachers.Count > 0) { schoolOb.Teachers?.ForEach(teacher => { teachers.Add(teacher); }); } List <Pupil> pupils = new List <Pupil>(); if (schoolOb.Pupils.Count > 0) { schoolOb.Pupils?.ForEach(pupil => { pupils.Add(pupil); }); } List <Admin> admins = new List <Admin>(); if (schoolOb.Admins.Count > 0) { schoolOb.Admins?.ForEach(adminItem => { admins.Add(adminItem); }); } return(AdminDB.AddSchoolWithDetails(schoolDetails, teachers, pupils, admins)); }