def test_true_2(self): self.assertTrue(arr_check([['string']]))
def test_true_1(self): self.assertTrue(arr_check([]))
def test_false_1(self): self.assertFalse(arr_check([[], {}]))
def test_false_2(self): self.assertFalse(arr_check(['A', 'R', 'R', 'A', 'Y']))
def test_true_3(self): self.assertTrue(arr_check([[1], [2], [3]]))