It might be required for you to import the package if you encounter any issues (like casting an Array), so better be safe than sorry and add the import.
import crafttweaker.entity.AttributeModifier;

ZenGetter	GetterMethod	Rückgabetyp
ZenGetter uuid	GetterMethod getUUID()	Rückgabetyp string
ZenGetter name	GetterMethod getName()	Rückgabetyp string
ZenGetter operation	GetterMethod getOperation()	Rückgabetyp int
ZenGetter amount	GetterMethod getAmount()	Rückgabetyp double
ZenGetter saved	GetterMethod isSaved()	Rückgabetyp boolean

SetterName	SetterMethod	Parameter Type
SetterName saved	SetterMethod setSaved(boolean)	Parameter Type boolean

 Copy
for operation:
0 = add: Increment X by Amount
1 = multiply_base: Increment Y by X * Amount
2 = multiply: Y = Y * (1 + Amount) (equivalent to Increment Y by Y * Amount).

ZenScript
 Copy
AttributeModifier.createModifier(String name, double amount, int operation, @Optional String uuid);