code: def run_command(self, stream=sys.stdout, dry_run=False):
          
          return run_gtapp(self.__app, stream, dry_run, **self.args)
docs: Runs the command for this link.  This method can be overridden by
          sub-classes to invoke a different command
  
          Parameters
          -----------
          stream : `file`
              Must have 'write' function
  
          dry_run : bool
              Print command but do not run it