Total fit (red solid line) of the Lyβ absorption line for the galaxy GP 1244+0216 (black data). The contributions from the stellar continuum (dashed red line), Lyβ absorption line (blue solid line), and O I absorption line (orange solid line) blend together. O I absorption lines at 989 and 1039 Å are unblended and robustly constrain the O I profile. All three components need to be accounted for when fitting the Lyman series.