docs: def add_page(self, page, default = True):
          r"""
          Add a display page to the display.
  
          :param page:  Page to be added
          :type display_id: ``DisplayPage``
  
          :param default: True if this page should be shown upon initialization.
              
          :type name: ``bool``
          """
          self._pages[page.page_id] = page
          page._add_display(self)
          if default or not self._active_page:
              self._active_page = page