在python中从xml转换为csv时追加到新行

import csv
import xml.etree.ElementTree as ET

def xml_to_csv(xml_file, csv_file):
    tree = ET.parse(xml_file)
    root = tree.getroot()

    with open(csv_file, 'a', newline='') as file:
        writer = csv.writer(file)
        
        for child in root:
            row = []
            for sub_child in child:
                row.append(sub_child.text)
            writer.writerow(row)

# 示例用法
xml_file = 'input.xml'
csv_file = 'output.csv'
xml_to_csv(xml_file, csv_file)