popen_example.py

import subprocess
import base64

def keyscan(host):
    p = subprocess.Popen(['/bin/sh', '-c', '(ssh-keyscan %s | grep ssh-rsa) 2>/dev/null' % host], stdout=subprocess.PIPE)
    config = p.stdout.read().decode('ascii').split(' ')
    p.wait()
    if p.returncode != 0:
        raise Exception("Could not scan %s for SSH key." % host)
    config[2] = paramiko.RSAKey(data=base64.b64decode(config[2]))
    return config