Python 调用 wget 下载总是报错，求指教，我只想知道为啥，谢谢！

cmd = ("sudo wget -P -N -o -c -O {} {}".format(save_path, link))
ref = subprocess.call(cmd, shell=True)
if ref != 0:
print("can't get download")
报以下两种错误
1.
http://pdf1.qimingpian.com/userUpload/file_59ad16e393da6.pdf
wget: missing URL


2.
http://pdf1.qimingpian.com/announcement_real/5a55c0a1f0a1a.pdf
/bin/sh: $'\346\270\270\346\210\217\345\207\272\346\265\267\346\212\245\345\221\212\357\274\232\344\270\234\345\215\227\344\272\232\347\257\207-40\351\241\265.pdf': command not found
can't get download