fix bug

@@ -93,7 +93,7 @@ class Command(BaseCommand, LoggerMixin):
         task_str, is_priority = rh.dequeue()
         if task_str is None:
             self.online_log.info('{0} [get_doc_info] [queue empty]'.format(self.log_base))
-            return None, None, None, None, None
+            return None, None, None, None
 
         self.online_log.info('{0} [get_doc_info] [task={1}] [is_priority={2}]'.format(
             self.log_base, task_str, is_priority))
@@ -114,11 +114,11 @@ class Command(BaseCommand, LoggerMixin):
             if doc is None:
                 self.online_log.warn('{0} [get_doc_info] [doc not exist] [task_str={1}] [is_priority={2}]'.format(
                     self.log_base, task_str, is_priority))
-                return None, None, None, None, None
+                return None, None, None, None
             elif doc.status != DocStatus.INIT.value:
                 self.online_log.warn('{0} [get_doc_info] [doc status error] [task_str={1}] [is_priority={2}] '
                                      '[doc_status={3}]'.format(self.log_base, task_str, is_priority, doc.status))
-                return None, None, None, None, None
+                return None, None, None, None
             doc.status = DocStatus.PROCESSING.value
             doc.start_time = timezone.now()
             doc.save()