How to setup "drush @mysite.env ssh" command? I am trying to create a custom drush command in which I have to access another remote environment and run some drush commands there. The problem is I am unable to ssh to another environment e.g, "dev" etc.
I am able to run

drush @mysite.env status


but when I try

drush @mysite.env ssh 


then I get this error 

PTY allocation request failed on channel 0
Command not supported as typed.
An error 255 occurred while running the command `ssh -p 2222 -o AddressFamily inet"


"pantheon.aliases.drushrc.php" is placed in "~/.drush" folder.

Please let me know what's missing.

Thanks
Pantheon does not support ssh access to your server. Write your own Drush command, place it in the drush folder at your repository root, and call it with drush @mysite.env mycommand.