def validate_readable_id(cls, v: Optional[str]) -> Optional[str]:
        """Validate that readable_id is a valid lowercase string with hyphens only."""
        if v is None:
            return None
        if not all(c.islower() or c.isdigit() or c == "-" for c in v):
            raise ValueError(
                "readable_id must contain only lowercase letters, numbers, and hyphens"
            )
        # Check that readable_id doesn't start or end with a hyphen
        if v and (v.startswith("-") or v.endswith("-")):
            raise ValueError("readable_id must not start or end with a hyphen")
        return v
Validate that readable_id is a valid lowercase string with hyphens only.
backend/airweave/schemas/collection.py