The FactoryBot.modify class method defines a block with an overriding factory method available. That is the only method you can call within the block.

The factory method within this block takes a mandatory factory name, and a block. All other arguments are ignored. The factory name must already be defined. The block is a normal factory definition block. Take note that hooks cannot be cleared and continue to compound.

For details on why you'd want to use this, see the guide.