getColumn method
Returns a list of Cell
at row # colNum
Implementation
List<Cell> getColumn(int colNum) {
throwIfInvalid(new Position(row: 0, column: colNum));
List<Cell> _tmpCol = [];
for (int c = 0; c < 9; c++) {
_tmpCol.add(_matrix![c][colNum]);
}
return _tmpCol;
}