Function read_dataset_dir 

pub fn read_dataset_dir(
    dir: impl AsRef<Path>,
    from: &str,
    scenario: i64,
) -> Result<GridfmRead>

Read one scenario of a dataset directory in the named from format: the directory sibling of powerio::parse_file, and the one place dataset format names are dispatched (the C ABI’s pio_read_dir is a thin wrapper). gridfm is the one dataset format today; scenario selects within it. PyPSA CSV directories are case inputs, not datasets, and parse through parse_file.

Errors

powerio::Error::UnknownFormat for a non-dataset format name; otherwise as read_gridfm_dataset.