问如何使用字符串类型全局变量填充MDLable文本字段。我还需要设置字体和大小

EN

import kivy
from kivymd.app import MDApp
from kivy.uix.widget import Widget
from kivy.properties import ObjectProperty
from kivymd.uix.screen import Screen
from kivymd.uix.label import MDLabel
from kivymd.uix.boxlayout import BoxLayout
from kivymd.uix.floatlayout import MDFloatLayout
from kivy.lang.builder import Builder

#Global variable from a dictionary
orch_hostName = str("some text to add to a MDLabel")

class MyGui(Screen):
    orch_info = ObjectProperty(None)   
    def on_enter(self):
        orch_info1 = orch_hostName
        self.ids.orch_info.text = "orch_info1"

class MainApp(MDApp):
    def build(self):
        
        self.theme_cls.primary_palette = "Gray"
        self.theme_cls.theme_style = "Light"
        self.theme_cls.primary_hue = "300"
        
    
        return MyGui()
        
        
if __name__ == "__main__":
    MainApp().run()

##################################################
KV File
Widget:
<MyGui>
    orch_info: orch_info
    MDFloatLayout:
        MDLabel:
            id: orch_info
            multiline: True
            halign: 'left'
            markup: True
            theme_text_color: 'Custom'
            text_color: (105 / 255.0, 105 / 255.0, 105 / 255.0, 1)
            text: ""
            font_style: 'H1'
            pos_hint: {'x': .85, 'y': .47}