kivy.factory.FactoryException: Unknown class <I>

Question

from kivymd.app import MDApp
from kivy.lang import Builder


class Test(MDApp):

    def build(self):
        self.title ='Programming'
        self.theme_cls.primary_palette = "Blue"
        return Builder.load_string(
            '''
BoxLayout:
    orientation:'vertical'
    MDToolbar:
        title:'Programming'
        md_bg_colour:app.theme_cls.primary_color
        specific_text_color:1,1,1,1
        
    
    MDBottomNavigationItem:
        name: 'screen 1'
        text: 'Python'
        icon: 'language-python'
        
        Image:
            id: imageView
            source: 'python.png'
            
    MDBottomNavigationItem:
        name: 'screen 2'
        text: 'C++'
        icon: 'language-cpp'
        
        Image:
            id: imageView
            source: 'cp.png'
        
    MDBottomNavigationItem:
        name: 'screen 3'
        text: 'Kivy'
        icon: 'android'
        
        Image:
            id: imageView
            source: 'kivy.png'
        I    
        
'''
        )

Test().run()