internal ContractSide(DateTime date, Proposal parent, SideController sideController)
{
SideController = sideController;
Parent = parent;
EntryType action = parent.IsEveneSide(this) ? parent.Action : Graph.SideKey.OppositeType(parent.Action);
SideKey = Graph.SideKey.Get(date, action);
SideController.Register(this);
}