/// <summary>
/// Returns a hash code for this instance.
/// </summary>
/// <returns>
/// A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table.
/// </returns>
public override int GetHashCode()
{
return(Block.GetHashCode() ^
MapArea.GetHashCode() ^
QuarterUnit.GetHashCode() ^
Series.GetHashCode() ^
Sheet.GetHashCode() ^
Unit.GetHashCode());
}