Unable to use subset command to create subcategories of a dataset

[itasky]

The TrainDataSet node does not support the subset function to create further subcategories of the main dataset

https://github.com/kohya-ss/sd-scripts/blob/main/docs/config_README-en.md
A subset is a partition of the dataset by image directory or metadata. Several subsets make up a dataset.
Options such as keep_tokens and flip_aug can be set for each subset. On the other hand, options such as resolution and batch_size can be set for each dataset, and their values are common among subsets belonging to the same dataset. More details will be provided later.