def METHOD_NAME(self):
    setdefaultattr(
        self,
        "length_unit",
        self.quan(1.0, self.parameters.get("length_unit", "kpc")),
    )
    setdefaultattr(
        self,
        "velocity_unit",
        self.quan(1.0, self.parameters.get("velocity_unit", "kpc/Gyr")),
    )
    setdefaultattr(
        self, "time_unit", self.quan(1.0, self.parameters.get("time_unit", "Gyr"))
    )
    mass_unit = self.parameters.get("mass_unit", "1e10 Msun")
    if " " in mass_unit:
        factor, unit = mass_unit.split(" ")
    else:
        factor = 1.0
        unit = mass_unit
    setdefaultattr(self, "mass_unit", self.quan(float(factor), unit))