def test_negation(a):
    everythingbutA = a.everythingbut()
    assert everythingbutA.accepts('')
    assert (not everythingbutA.accepts('a'))
    assert everythingbutA.accepts('b')
    assert everythingbutA.accepts('aa')
    assert everythingbutA.accepts('ab')
def test_negation(a):
    everythingbutA = a.everythingbut()
    assert everythingbutA.accepts()
    assert (not everythingbutA.accepts('a'))
    assert everythingbutA.accepts('b')
    assert everythingbutA.accepts('aa')
    assert everythingbutA.accepts('ab')