public void Add_Nanny(Nanny nanny1)
        {
            int age = (DateTime.Now.Subtract(nanny1.Birth_Date).Days);//we make minus between now and birth date and take all the days that she lives

            if (age / 365 < 18)
            {
                throw new Exception("cant add nanny less then 18 years");
            }
            for (int i = 0; i < 7; i++)//check end isnt smaller then begining
            {
                if (nanny1.Work_Hours[1, i] < nanny1.Work_Hours[0, i])
                {
                    throw new Exception("wrong hours format");
                }
            }
            my_dal.Add_Nanny(nanny1);
        }