def _get_branch(self, branch: Optional[str], __user__: dict = None) -> str:
        """Get effective branch with priority resolution."""
        if branch:
            return branch
        if __user__ and "valves" in __user__:
            user_valves = __user__.get("valves") if __user__ else None
            if self.valves.ALLOW_USER_OVERRIDES and user_valves.USER_DEFAULT_BRANCH:
                return user_valves.USER_DEFAULT_BRANCH
        return self.valves.DEFAULT_BRANCH