public override void Remove(Company c) { }
public override void Remove(Company c) { children.Remove(c); }
public override void Add(Company c) { }
public abstract void Remove(Company c);
public override void Add(Company c) { children.Add(c); }
public abstract void Add(Company c);
public override void Remove(Company company) { children.Remove(company); }
public override void Add(Company company) { children.Add(company); }