Advice on connected objects.

[strange igloo]

I need some advice. There's a lot of ways I can think of to do this, but basically, I have a List of "things", and I want to validate that the right "things" are plugged together (In this case, in a valid order)

Should I use an Enum, Child Classes, or something else, for defining the various "types" of thing that can be in the list, and compared to make sure they're valid things to be connected together?

If this isn't enough context, below is the exact usecase I'm working on:

||I am working on a custom skills system, in which players can plug together "Scroll Pieces" to create skills. Like combining [Dragoon Jump] -> [Swing Sword] to create a new action. These "Scroll Pieces" need to have valid/invalid things they can be attached to- You can't connect multiple things that open a menu to control the skill, for example.||

[bleak sinew]

Enums, separate classes or even strings are valid options. I'd also consider SO instances as type definitions.
Then you just need to configure a dict of lists or a list of lists determining what each type can connect with.
An SO would make it even easier, as you would be able to define a list or several(for different sides for example) of other types that you can connect to this one.