Tuple7<T1, T2, T3, T4, T5, T6, T7>.fromList  constructor 
      
      Tuple7<T1, T2, T3, T4, T5, T6, T7>.fromList (
    
- List items
Create a new tuple value with the specified list items.
Implementation
factory Tuple7.fromList(List items) {
  if (items.length != 7) {
    throw ArgumentError('items must have length 7');
  }
  return Tuple7<T1, T2, T3, T4, T5, T6, T7>(
      items[0] as T1,
      items[1] as T2,
      items[2] as T3,
      items[3] as T4,
      items[4] as T5,
      items[5] as T6,
      items[6] as T7);
}