@@ -0,0 +1,563 @@
+package seedu.tache.logic.commands;%0A%0Aimport seedu.tache.logic.commands.exceptions.CommandException;%0A%0Apublic interface Undoable %7B%0A%0A    //@@author A0150120H%0A    /**%0A     * Returns true if the command can be undone.%0A     */%0A    public abstract boolean isUndoable();%0A%0A    //@@author A0150120H%0A    /**%0A     * Attempts to undo the command.%0A     * If the undo is successful, returns the CommandResult feedback string of the original command%0A     * @throws CommandException if the undo operation fails%0A     */%0A    public abstract String undo() throws CommandException;%0A%7D%0A

Create Undoable interface