public Head(Table table) : base(table)
 {
     columns = new FluentCollection <Column, Head>(this)
     {
         GetInstance = () => { return(new Column()); }
     };
 }
 public Line(Body body)
 {
     if (body == null)
     {
         throw new ArgumentNullException("body");
     }
     this.body = body;
     items     = new FluentCollection <Item, Line>(this)
     {
         GetInstance = () => { return(new Item()); }
     };
 }