批量更改图片名称

import os
filepath = r'E:\ML\Pytorch\train\cleavage/'
n= 0
if __name__ == "__main__":
    print("start")
    if not os.path.exists(filepath):
        print("目录不存在!!")
        os._exit(1)
    filenames = os.listdir(filepath)
    for data in filenames:
        oldname = filepath + filenames[n]
      
        newname = n
        print(newname)
        newname=filepath + 'cleavage' + '_' +str(n) + '.jpg'
        os.rename(oldname,newname)
        n=n+1