如何使用Paramiko传递命令行ssh参数？

我正在尝试从使用Popen直接运行ssh命令迁移到使用Paramiko，因为我的代码正在迁移到该ssh命令不可用的环境。

当前命令的调用将传递一个参数，然后由远程服务器使用。换一种说法：

process = subprocess.Popen(['ssh', '-T', '-i<path to PEM file>', 'user@host', 'parameter'])

并且authorised_keys在远程服务器上具有：

command="/home/user/run_this_script.sh $SSH_ORIGINAL_COMMAND", ssh-rsa AAAA...

因此，我编写了以下代码来尝试模拟这种行为：

def ssh(host, user, key, timeout):
    """ Connect to the defined SSH host. """
    # Start by converting the (private) key into a RSAKey object. Use
    # StringIO to fake a file ...
    keyfile = io.StringIO(key)
    ssh_key = paramiko.RSAKey.from_private_key(keyfile)
    host_key = paramiko.RSAKey(data=base64.b64decode(HOST_KEYS[host]))
    client = paramiko.SSHClient()
    client.get_host_keys().add(host, "ssh-rsa", host_key)
    print("Connecting to %s" % host)
    client.connect(host, username=user, pkey=ssh_key, allow_agent=False, look_for_keys=False)
    channel = client.invoke_shell()

    ... code here to receive the data back from the remote host. Removed for relevancy.

    client.close()

为了将参数传递给远程主机，以便将其用作参数，我需要更改什么$SSH_ORIGINAL_COMMAND？