Docker exec command with Popen in Python

I am developing an application in which I interact with docker containers.

I want to execute this command in the docker exec name_of_container command : command= "/usr/bin/balance -b "+ ip_address + " 5001 " + servers_list

The idea is to make the echo command → / etc / supervisor / conf.d / supervisord.conf`

I tried the following:

p=subprocess.Popen(['docker','exec','supervisor','echo','command'], stdin=subprocess.PIPE, stdout=subprocess.PIPE)

but that won't work.

This is the error code:

exec: "'/usr/bin/balance -b 195.154.12.1 5001 192.186.13.1' >> /etc/supervisor/conf.d/supervisord.conf": stat '/usr/bin/balance -b 195.154.12.1 5001 192.186.13.1' >> /etc/supervisor/conf.d/supervisord.conf: no such file or directory