public static CreativeTeam <TCountry> operator -(CreativeTeam <TCountry> gr, Artist <TCountry> art) //deleting artist from group
{
CreativeTeam <TCountry> res = gr;
res.Members = gr.Members.Where(val => val != art).ToList();
return(res);
}
public static CreativeTeam <TCountry> operator +(CreativeTeam <TCountry> gr, Artist <TCountry> ar) //adding artist to the group
{
CreativeTeam <TCountry> res = gr;
res.Members.Add(ar);
return(res);
}