text: #!/usr/bin/env python
  """
  get_password function that displays asterisks instead of the actual characters.
  With the addition of a ControlT shortcut to hide/show the input.
  """
  from __future__ import unicode_literals
  from prompt_toolkit import prompt
  from prompt_toolkit.key_binding.defaults import load_key_bindings_for_prompt
  from prompt_toolkit.keys import Keys
  from prompt_toolkit.filters import Condition
  
  
  def main():
      hidden = [True] # Nonlocal
      registry = load_key_bindings_for_prompt()
  
      @registry.add_binding(Keys.ControlT)
      def _(event):
          ' When ControlT has been pressed, toggle visibility. '
          hidden[0] = not hidden[0]
  
  
      print('Type Control-T to toggle password visible.')
      password = prompt('Password: ',
                        is_password=Condition(lambda cli: hidden[0]),
                        key_bindings_registry=registry)
      print('You said: %s' % password)
  
  
  if __name__ == '__main__':
      main()
  