public DiagnosticReferral(String serialNumber, DateTime date, string notes, DiagnosticType diagnosticType) : base(serialNumber, date, notes)
 {
     this.diagnosticType = diagnosticType;
 }
 public DiagnosticReferral(DateTime date, string notes, DiagnosticType diagnosticType) : base(Guid.NewGuid().ToString(), date, notes)
 {
     this.diagnosticType = diagnosticType;
 }