Не импортируется MDTextFieldRound

python code:

from kivymd.app import MDApp

from kivymd.theming import ThemeManager
from kivy.uix.boxlayout import BoxLayout

class Main(MDApp):
    theme_cls = ThemeManager()
    def build(self):
        pass


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

kivy code:

#:import MDTextFieldRound kivymd.uix.textfield.MDTextFieldRound
#:import MDTextField kivymd.textfields.MDTextField

BoxLayout:
    size_hint: (.8, .8)
    pos_hint: {"center_x": .5, "center_y": .5}
    orientation: "vertical"
    MDTextField:
        hint_text: "This is hint_text"
        helper_text: "This is helper_text"
        helper_text_mode: "on_focus"

    MDTextFieldRound:   
        icon_left: "lock"