python 16进制string 转string

refs:

http://blog.csdn.net/u011546806/article/details/45370069

str = "7B 7D 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 32 0F 10 0A 4B 4C 00 00 00 00 00 00 00 00 3F 21"

def GetCmd(hexString):
            hexString = hexString.replace(" ", "");
            if ((len(hexString)  % 2) != 0):
                hexString += " ";
            bits = ""
            for x in range(0, len(hexString), 2):
                bits += chr(int(hexString[x:x+2], 16))
            return bits;