获取复杂层次的UI之后报错

执行部分代码如下：
```
for item in poco("android.widget.LinearLayout").offspring("android:id/content"):
if item not in listitem:
listitem.append(item)
print(item.get_text())
```

在成功执行之后报错:

```
Ran 1 test in 4.785s
OK
[12:35:52][DEBUG] C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\airtest\core\android\static\adb\windows\adb.exe -P 5037 -s 93FAY0ALWN forward --remove tcp:17909
[12:35:52][DEBUG] C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\airtest\core\android\static\adb\windows\adb.exe -P 5037 -s 93FAY0ALWN forward --remove tcp:19526
Exception ignored in: '>
Traceback (most recent call last):
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\object_proxy.py", line 114, in __del__
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\client.py", line 63, in evaluate
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\transport\http.py", line 26, in send
hrpc.exceptions.TransportDisconnected: HTTPConnectionPool(host='127.0.0.1', port=19526): Max retries exceeded with url: / (Caused by NewConnectionError(': Failed to establish a new connection: [WinError 10061] ',))

Exception ignored in: '>
Traceback (most recent call last):
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\object_proxy.py", line 114, in __del__
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\client.py", line 63, in evaluate
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\transport\http.py", line 26, in send
hrpc.exceptions.TransportDisconnected: HTTPConnectionPool(host='127.0.0.1', port=19526): Max retries exceeded with url: / (Caused by NewConnectionError(': Failed to establish a new connection: [WinError 10061] ',))

Exception ignored in: '>
Traceback (most recent call last):
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\object_proxy.py", line 114, in __del__
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\client.py", line 63, in evaluate
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\transport\http.py", line 26, in send
hrpc.exceptions.TransportDisconnected: HTTPConnectionPool(host='127.0.0.1', port=19526): Max retries exceeded with url: / (Caused by NewConnectionError(': Failed to establish a new connection: [WinError 10061] ',))

Exception ignored in: '>
Traceback (most recent call last):
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\object_proxy.py", line 114, in __del__
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\client.py", line 63, in evaluate
File "C:\Users\D234\AppData\Local\Programs\Python\Python36\lib\site-packages\hrpc\transport\http.py", line 26, in send
hrpc.exceptions.TransportDisconnected: HTTPConnectionPool(host='127.0.0.1', port=19526): Max retries exceeded with url: / (Caused by NewConnectionError(': Failed to establish a new connection: [WinError 1006Exception ignored in: '>
```