Python Kivy Launcher File Backup

    from kivy.app import App
    from kivy.lang import Builder
    from kivy.uix.screenmanager import ScreenManager, Screen
    import sqlite3
    import datetime
    import shutil

    KV = """
    <ScreenManagement>:
        EntryInterface:
            name: 'test'
    <EntryInterface>:
        BoxLayout:
            TextInput:
                id: textInput
            Button:
                text:'Save'
                on_press: root.save()
        """
    class ScreenManagement(ScreenManager):
        pass

    class EntryInterface (Screen):
        def save(self):
            self.now = str(datetime.datetime.now())
            self.time = self.now[11:22]
            #formatting the text
            self.time = self.time.replace(':','_')
            self.time = self.time.replace('.','_')

            if(self.ids.textInput.text ==''):
                self.stuff = 'Blank'
            else: self.stuff = self.ids.textInput.text

            conn = sqlite3.connect("test.db")
            cur = conn.cursor()
            cur.execute("INSERT INTO test_table VALUES (:stuff)", {'stuff': self.stuff})
            conn.commit()
            conn.close()
            self.ids.textInput.text = ''

            shutil.copy('test.db','BACKUP_'+self.time+'.db')

    class TestApp(App):
        title = "Login Screen"
        def build(self):
            Builder.load_string(KV)
            return ScreenManagement()

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