The EnchantmentLevelSet Event is fired when the levels for the three potential enchantments are generated in the Enchantment Table.

You will need to cast the event in the function header as this class:
crafttweaker.event.EnchantmentLevelSetEvent
You can, of course, also import the class before and use that name then.

EnchantmentLevelSet Events implement the following interfaces and are able to call all of their methods/getters/setters as well:

• IEventPositionable

ZenGetter	ZenSetter	Return Type
ZenGetter world	ZenSetter ​	Return Type IWorld
ZenGetter enchantRow	ZenSetter ​	Return Type int
ZenGetter power	ZenSetter ​	Return Type int
ZenGetter item	ZenSetter ​	Return Type IItemStack
ZenGetter originalLevel	ZenSetter ​	Return Type int
ZenGetter level	ZenSetter level	Return Type int

ZenGetter	ZenSetter	Type
ZenGetter position	ZenSetter ​	Type IBlockPos
ZenGetter x	ZenSetter ​	Type int
ZenGetter y	ZenSetter ​	Type int
ZenGetter z	ZenSetter ​	Type int

event.enchantRow lists the row (1-3) of the Enchantment Table, while event.originalLevel represents the original level of the row. event.power is the cumulative value of bookshelves surrounding the Enchantment Table, while event.item is the item that is being enchanted.

event.level can be arbitrarily modified to a value between 0 & 30.