private void ModifyButton_Click(object sender, EventArgs e)
        {
            var form3 = new RegisterLibrarianForm();

            form3.LoadDataForEdit(this.UserName, this.UserBirthday);
            form3.Closed += (s, args) => this.LoadingLibrarianData();
            form3.ShowDialog();
        }
        private void NewLibrarianButton_Click(object sender, EventArgs e)
        {
            var form2 = new RegisterLibrarianForm();

            form2.ShowDialog();
        }