Get Biome Registry Name

Hello,

I'm currently making a mod that allows the spread of biomes. I'm doing this by having the blocks spread like usual, however I'm making the biome spread with it as well. I'm using the /fillbiome command to do this. The issue I'm running into is, I'm wanting the player to be able to spread any biome they want by placing the "machine" in that biome, and setting it on top of a special block.

The way I plan on doing this, is by having the "machine" detect the biome at the current location, it saves the biome registry name in the "machine" then spreads that biome by joining different segments of strings together to finish the /fillbiome command.

The issue is, there is no "Get biome registry name" block at all, so I've been trying to use custom code snippets. But I have had no luck unfortunately. I've gotten close to figuring it out, however either MCreator or Java doesn't recognize the syntax.

And before anyone answers, yes, I am aware that there is a "Is biome at x y z <biome>", however I'm not looking to return a bool, I'm wanting it to return a string.

My problem is:

Is there a way to achieve returning a biome registry name?