def METHOD_NAME(self, errors: str = "ignore"):  # noqa: C901
    """Load CTD-Reference data and return a xarray.DataSet"""
    ds = super().METHOD_NAME(errors=errors)
    ds = ds.rename({"SOURCE": "EXPOCODE"})
    ds["DIRECTION"] = xr.full_like(ds["EXPOCODE"], "A", dtype=str)
    g = []
    for iplatform, grp in enumerate(ds.groupby("EXPOCODE")):
        code, this_ds = grp
        for istation, sub_grp in enumerate(this_ds.groupby("TIME")):
            sub_grp[-1]["CYCLE_NUMBER"] = xr.full_like(
                sub_grp[-1]["TIME"], istation, int
            )
            sub_grp[-1]["PLATFORM_NUMBER"] = xr.full_like(
                sub_grp[-1]["TIME"], iplatform + 900000, int
            )
            g.append(sub_grp[-1])
    ds = xr.concat(
        g, dim="N_POINTS", data_vars="minimal", coords="minimal", compat="override"
    )
    ds.attrs["DATA_ID"] = "ARGO_Reference_CTD"
    ds.attrs["DOI"] = "-"
    # Cast data types and add variable attributes (not available in the csv download):
    ds = self._add_attributes(ds)
    ds = ds.argo.cast_types()
    return ds