def is_new_citation(self, citation_id: str) -> bool:
        """
        Check if this is the first occurrence of this citation ID.

        Args:
            citation_id: The citation ID to check

        Returns:
            True if this is the first time seeing this citation ID, False otherwise.
            Also adds the ID to seen_citation_ids if it's new.
        """
        if citation_id is None or citation_id == "":
            return False

        is_new = citation_id not in self.seen_citation_ids
        if is_new:
            self.seen_citation_ids.add(citation_id)
        return is_new

        Check if this is the first occurrence of this citation ID.

        Args:
            citation_id: The citation ID to check

        Returns:
            True if this is the first time seeing this citation ID, False otherwise.
            Also adds the ID to seen_citation_ids if it's new.
        
py/core/utils/__init__.py