Add author and category nodes to the graph

add_authors_categories.py

def add_categories(categories):
    # Adds category nodes to the Neo4j graph.
    query = '''
            UNWIND $rows AS row
            MERGE (c:Category {category: row.category})
            RETURN count(*) as total
            '''
    return conn.query(query, parameters = {'rows':categories.to_dict('records')})


def add_authors(rows, batch_size=10000):
    # Adds author nodes to the Neo4j graph as a batch job.
    query = '''
            UNWIND $rows AS row
            MERGE (:Author {name: row.author})
            RETURN count(*) as total
            '''
    return insert_data(query, rows, batch_size)


def insert_data(query, rows, batch_size = 10000):
    # Function to handle the updating the Neo4j database in batch mode.
    
    total = 0
    batch = 0
    start = time.time()
    result = None
    
    while batch * batch_size < len(rows):

        res = conn.query(query, 
                         parameters = {'rows': rows[batch*batch_size:(batch+1)*batch_size].to_dict('records')})
        total += res[0]['total']
        batch += 1
        result = {"total":total, 
                  "batches":batch, 
                  "time":time.time()-start}
        print(result)
        
    return result

Line 33 parenthesis error?