def test_formula_string4(): assert sat._formula_str(['a', ['b', 'c']]) == '(a & (b | c))'
def test_formula_string5(): assert sat._formula_str(['a', ['b', ['c', 'd']]]) == '(a & (b | (c & d)))'
def test_formula_string2(): assert sat._formula_str(['a', 'b']) == '(a & b)'
def test_formula_string3(): assert sat._formula_str(['a', ['b']]) == '(a & (b))'
def test_formula_string1(): assert sat._formula_str(['a']) == '(a)'
def test_formula_string5(): assert sat._formula_str(["a", ["b", ["c", "d"]]]) == "(a & (b | (c & d)))"
def test_formula_string4(): assert sat._formula_str(["a", ["b", "c"]]) == "(a & (b | c))"
def test_formula_string3(): assert sat._formula_str(["a", ["b"]]) == "(a & (b))"
def test_formula_string2(): assert sat._formula_str(["a", "b"]) == "(a & b)"
def test_formula_string1(): assert sat._formula_str(["a"]) == "(a)"