subprocess模块的call报错

Arthur_

如下代码报错：

我想一段buf包含字符串和二进制信息作为参数传递， 请问如何处理呢
  File "/usr/lib/python2.7/subprocess.py", line 522, in call
    return Popen(*popenargs, **kwargs).wait()
  File "/usr/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1327, in _execute_child
    raise child_exception
TypeError: execv() arg 2 must contain only strings


#!/usr/bin/python
import struct
from subprocess import call

a=0xa00510

#endianess convertion
def conv(num):
return struct.pack("<I",num)
buf="1234"
buf+=conv(a)
print buf
call(["./check", buf])