silly bugfix

insert/pg_insert.py

@@ -54,7 +54,7 @@ def format_node_query(node_list: Sequence[Node]) -> QueryList:
 
 def format_nodes_single_statement(node_list: Sequence[Node]) -> Query:
     node_json = [val for _, type, node in node_list for val in (type, json.dumps(node))]
-    query_str = f"INSERT INTO vertex (type, content)  VALUES {",".join("(%s,%s)"*len(node_list))}"
+    query_str = f"INSERT INTO vertex (type, content)  VALUES {",".join(["(%s,%s)"]*len(node_list))}"
     return (query_str, node_json)