def METHOD_NAME(clean_astro_ui):
    """We get an error if fit has not been called"""
    ui.load_arrays(2, [1, 5], [1, 12], ui.Data1D)
    cmdl = ui.const1d.cmdl
    pmdl = ui.polynom1d.pmdl
    cmdl.c0 = 1.5
    pmdl.c0 = -5
    pmdl.c1 = 2
    ui.set_source(2, cmdl + pmdl)
    with pytest.raises(SessionErr) as exc:
        ui.eqwidth(cmdl, cmdl + pmdl, id=2, error=True)
    assert str(exc.value) == 'no fit has been performed'