def METHOD_NAME(self):
    assert self.gruneisen_obj.thermal_conductivity_slack() == approx(77.97582174520458)
    assert self.gruneisen_obj.thermal_conductivity_slack(t=300) == approx(88.94562145031158)
    assert self.gruneisen_obj_Si.thermal_conductivity_slack(t=300) == approx(127.69008331982265)