protected bool Equals(BasicPersonInformation other)
 {
     return PersonId == other.PersonId &&
         string.Equals(FirstName, other.FirstName) &&
         string.Equals(LastName, other.LastName) &&
         string.Equals(CompanyName, other.CompanyName);
 }
 private void GetBasicInformationOnSeller()
 {
     var newBasicInfoOnSeller = new BasicPersonInformation
     {
         PersonId = 1,
         FirstName = "Michał",
         LastName = "Rakel",
         CompanyName = "brak"
     };
     _personInformations.Add(newBasicInfoOnSeller);
 }