Question about the `# Copied from` system

Hi team! 👋

While working on improving docstrings and type hints across scheduler files (issue #9567), I've noticed the # Copied from pattern used extensively throughout the codebase.

Examples:

• Functions like betas_for_alpha_bar are duplicated across multiple schedulers
• Output classes like DDPMSchedulerOutput are copied with name replacements (e.g., DDPM->EulerDiscrete)

My question: What's the rationale behind this duplication system instead of:

1. Using a shared utils.py or common.py file for common functions
2. Using class inheritance for similar Output classes

I understand there might be good architectural reasons (module independence, API stability, avoiding circular dependencies, etc.), but this isn't documented anywhere that I could find.

Suggested action: Regardless of the answer, I think we should either:

• Option A: Refactor to use inheritance/shared utilities (if the current system is legacy)
• Option B: Document this design decision in:
    - A CONTRIBUTING.md or architecture doc
    - Comments in the utils/check_copies.py script itself
    - Another README in the diffusers directory

This would help future contributors (like me! 😅) understand why this pattern exists and how to work with it properly when improving documentation. What do you think?

Thanks for maintaining such a great library! 🚀

Inizia leggendo gli esempi di scheduler menzionati nell’issue e utils/check_copies.py, quindi esamina la discussione per individuare eventuali decisioni su duplicazione, utilità condivise o ereditarietà. L’attività è completata quando la motivazione e il workflow per i contributori sono documentati in una posizione concordata, come CONTRIBUTING.md, un documento di architettura o commenti nello script di controllo delle copie.