question: undo the last executed or redone operation . after this , the board , including the game if it has one , will be restored to the state it was in before the operation was issued . concode_field_sep Vector ops concode_elem_sep int firstNewOp concode_elem_sep Vector ops concode_elem_sep HistoryList instance concode_elem_sep long serialVersionUID concode_field_sep Operation redoOperation concode_elem_sep Vector getOperations concode_elem_sep Vector getOperations concode_elem_sep void addOperation concode_elem_sep Object getEmptyState concode_elem_sep boolean canRedo concode_elem_sep int lastDoneOperation concode_elem_sep boolean canUndo concode_elem_sep void clearHistory concode_elem_sep int totalNumberOfOperations concode_elem_sep Object getState concode_elem_sep int getFirstNewOp concode_elem_sep void undoOperations concode_elem_sep void setState concode_elem_sep HistoryList getInstance concode_elem_sep void redoOperations
target: Operation function ( ) { firstNewOp -- ; Operation loc0 = ( Operation ) ( ops . elementAt ( firstNewOp ) ) ; loc0 . undo ( ) ; return loc0 ; }