what is the code in kivy if i press enter to go to next line in text box code example

Example: kivy password mask

from kivy.base import runTouchApp
from kivy.lang import Builder

KV = ''' 
BoxLayout:
    CheckBox:
        id: cb
    TextInput:
        password: True
        multiline: cb.active
'''

runTouchApp(Builder.load_string(KV))