The core shard set, filtered to those actually present and non-empty in con.
Use it to drive write_parquet_outputs() so a dataset with no obs_attribute
(most of them) does not emit an empty file.
The core shard set, filtered to those actually present and non-empty in con.
Use it to drive write_parquet_outputs() so a dataset with no obs_attribute
(most of them) does not emit an empty file.