refactor: make methods use the MISSING value

[EdVraz]

About

This pull request refactors methods to use the MISSING value

Checklist

• I've ran pre-commit to format and lint the change(s) made.
• I've checked to make sure the change(s) work on 3.8.6 and higher.
• This fixes/solves an Issue.
  • (If existent):
• I've made this pull request for/as: (check all that apply)
  • Documentation
  • Breaking change
  • New feature/enhancement
  • Bugfix

[i0bs]

I'm not going to comment on every single file needing the Optional, but they should target the object that they need. For example, embeds should be Optional[Union[Embed, List[Embed]] and vice versa.

[EdVraz]

But i can't import it due to circular import

And if I'd put it there without having it imported I'd not pass the pre-commit

[i0bs]

How are you hitting circular imports?
Additionally, if there is no way for you to realistically import it, set the type annotation with a string. "Embed" can also suffice.

[EdVraz]

How are you hitting circular imports? Additionally, if there is no way for you to realistically import it, set the type annotation with a string. "Embed" can also suffice.

Message is importing Channel and member, so I can't import Embed from Message

ok, I'll do that