def add_sky(config):
    """Add sky temperature model, EoR, and foregrounds, using defaults."""
    sky_config = """
sky:
    Tsky_mdl: !Tsky
        datafile: HERA_Tsky_Reformatted.npz
        interp_kwargs:
            pol: xx
    eor:
        noiselike_eor: {}
    foregrounds:
        diffuse_foreground: {}
        pntsrc_foreground: {}
"""
    return config + sky_config[1:]