Mysterious error with Cypher Query: "Type mismatch: expected Map, Node, Relationship,..."

    def all_morphisms(self):
        results, meta = db.cypher_query(
            f"MATCH (X:QuiverNode)-[r:MAPS_TO]->(:QuiverNode)"
            f"MATCH (f:QuiverArrow) "
            f"WHERE X.uid='{self.uid}' AND f.uid=r.uid "
            f"RETURN f")
        return [QuiverArrow.inflate(row[0]) for row in results]
                    
    def delete(self):
        # Delete all the outgoing morphisms first:
        db.cypher_query(f"MATCH (X:QuiverNode)-[r:MAPS_TO]->(:QuiverNode)"
                        f"MATCH (f:QuiverArrow) "
                        f"WHERE X.uid='{self.uid}' AND f.uid=r.uid DELETE f")  
        # TODO: see if we need to also delete r here ("DELETE r,f"), or whether the following automatically deletes it:
        super().delete()
           

That's how you do it: a multi-match statement.