python 删除文件中指定行

代码适用情况：
xml文件，循环出现某几行，根据这几行中的某个字段删掉这几行
这段代码的作用删除jenkins中config.xml中在自动生成pipline报错的时的回滚

start = '<se.diabol.jenkins.pipeline.DeliveryPipelineView plugin='
end = '</se.diabol.jenkins.pipeline.DeliveryPipelineView>'
def delete_pip(src):
  f = open(src, 'r')
  lines = [];
  pip = []
  flag = True
  for line in f:
    if start in line:
      pip = [True]
      flag = False

    if flag:
      lines.append(line)
    else:
      pip.append(line)
      if pipline_name in line:
        pip[] = False

    if end in line:
      flag = True
      if pip[]:
        for i in pip[:]:
          lines.append(i)
  f.close()

  f = open(src, 'w')
  f.writelines(lines)
  f.close()