pieces_to_start_fen method Null safety
Implementation
static String pieces_to_start_fen(List<PieceType> pieces) {
assert(pieces.length == 8);
String blackPieces = pieces.map((p) => p.toLowerCase()).join('');
String whitePieces = pieces.map((p) => p.toUpperCase()).join('');
String pawns = 'p' * 8;
String _fen = '$blackPieces/$pawns/8/8/8/8/${pawns.toUpperCase()}/$whitePieces w KQkq - 0 1';
return _fen;
}