private void MergeRegistrations()
{
var allData = new List <Registrations>();
var dataInProper = new List <Registrations>();
for (int i = 0; i < databases.Length; i++)
{
var l = Registrations.Read(this.databases[i]);
if (i == 0)
{
dataInProper = l;
}
allData.AddRange(l);
}
var toWrite = this.SubtractHashSet(new HashSet <Registrations>(allData), new HashSet <Registrations>(dataInProper));
Registrations.Insert(this.proper, toWrite);
}
