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 at the very top of the file.

ZenScript
 Copy
import crafttweaker.api.block.entity.BannerPattern;

BannerPattern extends Record. That means all methods available in Record are also available in BannerPattern

Name	Type	Has Getter	Has Setter
Name assetId	Type ResourceLocation	Has Getter true	Has Setter false
Name commandString	Type string	Has Getter true	Has Setter false
Name registryName	Type ResourceLocation	Has Getter true	Has Setter false
Name translationKey	Type string	Has Getter true	Has Setter false