public bool SaveFile(PersonData person, string filePath)
        {
            _fileStream = !File.Exists(filePath)
                ? new FileStream(filePath, FileMode.OpenOrCreate, FileAccess.ReadWrite)
                : new FileStream(filePath, FileMode.Append, FileAccess.Write);

            try
            {
                _streamWriter = new StreamWriter(_fileStream);
                _streamWriter.WriteLine(person.ToString());
                _streamWriter.WriteLine(person.Surname);
                _streamWriter.WriteLine(person.Bank);
                _streamWriter.WriteLine(person.AccountNumber);
                _streamWriter.Close();
                return true;
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
                return false;
            }
        }