code: def output_deployment_diagnostics(awsclient, deployment_id, log_group, start_time=None):
      
      headline = False
      for instance_id in _list_deployment_instances(awsclient, deployment_id):
          diagnostics = _get_deployment_instance_diagnostics(
              awsclient, deployment_id, instance_id)
          #if error_code != 'Success':
          if diagnostics is not None:
              error_code, script_name, message, log_tail = diagnostics
              # header
              if not headline:
                  headline = True
                  log.info('\ndeployment diagnostics:')
              # event logs
              log.info('Instance ID: %s', Fore.MAGENTA + instance_id + Fore.RESET)
              log.info('Error Code:  %s', error_code)
              log.info('Script Name: %s', script_name)
              log.info('Message:     %s', message)
              log.info('Log Tail:    %s', log_tail)
              # cloudwatch logs
              if check_log_stream_exists(awsclient, log_group, instance_id):
                  logentries = get_log_events(
                      awsclient, log_group, instance_id,
                      datetime_to_timestamp(start_time))
                  if logentries:
                      log.info('instance %s logentries', instance_id)
                      for e in logentries:
                          log.info(e['message'].strip())
docs: diagnostics
  
      :param awsclient:
      :param deployment_id: