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