want := make([]Level3, 2)
	want[0] = Level3{
		Level2s: []Level2{
			{Level1: Level1{Value: "value1"}},
			{Level1: Level1{Value: "value2"}},
		},
	}
	if err := DB.Create(&want[0]).Error; err != nil {
		t.Error(err)
	}

	want[1] = Level3{
		Level2s: []Level2{
			{Level1: Level1{Value: "value3"}},
			{Level1: Level1{Value: "value4"}},
		},
	}
	if err := DB.Create(&want[1]).Error; err != nil {