def METHOD_NAME(universe, lipid_heads):
    lfls_ag = LeafletFinder(universe, lipid_heads, cutoff=15.0, pbc=True)
    lfls_ag.update()
    assert_almost_equal(lfls_ag.cutoff, 15.0, decimal=4)
    assert_almost_equal(len(lfls_ag.groups()), 2, decimal=4)