def METHOD_NAME(m, base="TDS"):
    """
    Builds RO model based on the IDAES separator.
    Requires prop_TDS property package.
    """
    prop = property_models.get_prop(m, base=base)
    m.fs.RO = Separator(
        property_package=prop,
        outlet_list=["retentate", "permeate"],
        split_basis=SplittingType.componentFlow,
        energy_split_basis=EnergySplittingType.equal_temperature,
    )
    # specify
    if base == "TDS":
        m.fs.RO.split_fraction[0, "permeate", "H2O"].fix(0.5)
        m.fs.RO.split_fraction[0, "permeate", "TDS"].fix(0.01)
    else:
        raise ValueError(
            "Unexpected property base {base} provided to build_SepRO"
            "".format(base=base)
        )
    # scale
    set_scaling_factor(
        m.fs.RO.split_fraction, 1
    )  # TODO: IDAES should set these scaling factors by default
    constraint_scaling_transform(m.fs.RO.sum_split_frac[0.0, "H2O"], 1)
    constraint_scaling_transform(m.fs.RO.sum_split_frac[0.0, "TDS"], 1)