I want to execute a Python script on several (15+) remote machine using SSH. After invoking the script/command I need to disconnect ssh session and keep the processes running in background for as long as they are required to. 
I have used Paramiko and PySSH in past so have no problems using them again. Only thing I need to know is how to disconnect a ssh session in python (since normally local script would wait for each remote machine to complete processing before moving on).
On Linux machines, you can run the script with 'at'. 
echo "python scriptname.py" ¦ at now
Execute remote python script via SSH