Keyerror while using XCamera

[USER4247]

I have made a small script to test out the XCamera but whenever i try loading the script , it shows an error

Exception has occurred: KeyError
'kivy.garden.xcamera'

here is the code

from kivy.lang import Builder
from kivy.app import App

kv = """
#: import XCamera kivy.garden.xcamera.XCamera
FloatLayout:
    orientation: "vertical"
    XCamera:
        id:xcam
        

"""

class Cam(App):
    def build(self):
        return Builder.load_string(kv)

if __name__ == "__main__":
    Cam().run()