docs: def page(request):
      """
      Adds the current page to the template context and runs its
      ``set_helper`` method. This was previously part of
      ``PageMiddleware``, but moved to a context processor so that
      we could assign these template context variables without
      the middleware depending on Django's ``TemplateResponse``.
      """
      context = {}
      page = getattr(request, "page", None)
      if isinstance(page, Page):
          # set_helpers has always expected the current template context,
          # but here we're just passing in our context dict with enough
          # variables to satisfy it.
          context = {"request": request, "page": page, "_current_page": page}
          page.set_helpers(context)
      return context