code: def load_extra_emacs_page_navigation_bindings():
      
      registry = ConditionalRegistry(Registry(), EmacsMode())
      handle = registry.add_binding
  
      handle(Keys.ControlV)(scroll_page_down)
      handle(Keys.PageDown)(scroll_page_down)
      handle(Keys.Escape, 'v')(scroll_page_up)
      handle(Keys.PageUp)(scroll_page_up)
  
      return registry
docs: Key bindings, for scrolling up and down through pages.
      This are separate bindings, because GNU readline doesn't have them.