Factory warning: Ignored class "MockTurtleForm" ?

[JTP-123]

I am a newbie and plan to learn kivy. Now I got stuck on one problem. I renamed some class AddLocationForm name as MockTurtleForm in each related replace, then when I run main.py, it reported:

[WARNING] [Factory ] Ignored class "MockTurtleForm" re-declaration. Current - module: None, cls: <class '__main__.MockTurtleForm'>, baseclass: None, filename: None. Ignored - module: None, cls: None, baseclass: BoxLayout, filename: C:\Users\sky\python_Work\kivy_project\weather.kv.

Also, I found all words of shipshape boxlayouts were cornered, that is, in lower-left corner on kivy screen.

I input some key words and found something maybe helpful in https://kivy.org/doc/stable/_modules/kivy/factory.html, then I did it in command line as instructions told , used Factory.unregister('AddLocationForm', cls=AddLocationForm) and Factory.register('MockTurtleForm', MockTurtleForm), but it failed as well as in texteditor. My question is, My first class is weather, not the lastest MockTurtleForm, so AddLocation should be not permanent. If so, why did it happen?

Here is kivy.file:

MockTurtleForm: 

<MockTurtleForm@BoxLayout>:
    orientation: "vertical"
    BoxLayout:
        Button: 
            text: "华东"
    BoxLayout:
        Button:
            text: "华南"
            size_hint_x: 1
        Button:
            text: "华南"
            size_hint_x: 1
        Button:
            text: "华北"
            size_hint_x: 1       
    RecycleView:
        item_strings:  ["华东", "华南", "华中", "华北"]

python code is:

import kivy
kivy.require('2.3.1')

class WeatherApp(App):
    pass

class MockTurtleForm(BoxLayout):
    def size(self):
        print("text")