You don't need to set code for every action now.
Now you have one code for everything.
How to use it:
item.setLeftAction(core.createRunnable("<code>"))
item.setLeftSAction(core.createRunnable("<code>"))
item.setRightAction(core.createRunnable("<code>"))
item.setRightSAction(core.createRunnable("<code>"))
item.setShiftAction(core.createRunnable("<code>"))
item.setDropAction(core.createRunnable("<code>"))
item.setPieceBonus(core.createRunnable("<code>"))
item.setDamageEvent(core.createRunnable("<code>"))