code: def exec_command(self, cmdstr):
          
          if self.is_terminated:
              raise TerminatedError("this TerminalClient instance has been terminated")
  
          log.debug("sending command: %s", cmdstr)
          c = Command(self.app, cmdstr)
          start = time.time()
          c.execute()
          elapsed = time.time() - start
          log.debug("elapsed execution: {0}".format(elapsed))
          self.status = Status(c.status_line)
  
          return c
docs: Execute an x3270 command
  
              `cmdstr` gets sent directly to the x3270 subprocess on it's stdin.