yasa.Hypnogram.n_stages

property Hypnogram.n_stages

The number of allowed sleep stages in the hypnogram (2, 3, 4, or 5). This reflects the hypnogram type set at construction time, not the number of unique stages actually present in the data. For example, a hypnogram with only N2 and REM epochs will still report n_stages=5 if it was created as a 5-stage hypnogram. Artefact (ART) and Unscored (UNS) are always allowed and are not counted.