Is the is single method incorrect for next gui slot?

[Fusezion]

Description

I ran into an error for using set {_slot} to next gui slot saying a single variable can't be set to more than one object, after looking at the code I've come to realize that the comparison for isSingle might be incorrect.

Code in Question

skript-gui/src/main/java/io/github/apickledwalrus/skriptgui/elements/expressions/ExprNextGUISlot.java

Lines 75 to 78 in 5e6c741

	@Override
	public boolean isSingle() {
	return guis != null && guis.isSingle();
	}

My View
the condition guis != null && guis.isSingle() should be guis == null || guis.isSignle(), since the system should output true if it's null otherwise return what the expression says it is.

Note

I'm aware this should have been a bug report, but didn't wanna log into my server to get the version information or screenshots

[LohsMC]

Is that why I keep getting this message when sending the next gui slot?

[Fusezion]

No

[APickledWalrus]

sounds like a bug :) thought i replied to this already but it is on my radar