code: def wait_for_command_termination(self):
      self._command_thread.join()
  
imports: import threading
  import time
  from bluefog.run.horovodrun.common.util import network
  from bluefog.run.horovodrun.common.util import safe_shell_exec
label_desc: Use image node_id 6 for calling the BasicTaskService obj's underlying member method code with example usage: obj.wait_for_command_termination() without return types