I don't think it's docker-py's burden to do anything other than ' '.join(container_args)
If our transforms return strings that might have spaces, they also need to be quoted.
Also random note:
  
  
    
        
          |  | the item to a bind mounted volume, and returns the container path of the directory. | 
    
   
 
I believe this returns a full file path, not a parent directory path.