记Python使用lxml保存时pretty_print失效问题

读取时需自定义解析器添加remove_blank_text=True来移除原文件的空格
这样保存的时候pretty_print=True才会真正有效
参考: https://blog.csdn.net/xcookies/article/details/78647242

parser = etree.XMLParser(remove_blank_text=True)
tree = etree.parse(filename, parser)
root = tree.getroot()

# some operation
# ...

tree.write(outpath, pretty_print=True, xml_declaration=True,  encoding='utf-8')