text: from aiohttp import web
  
  from aiohttp_pydantic import PydanticView
  
  
  class View1(PydanticView):
      async def get(self, a: int, /):
          return web.json_response()
  
  
  class View2(PydanticView):
      async def post(self, b: int, /):
          return web.json_response()
  
  
  sub_app = web.Application()
  sub_app.router.add_view("/route-2/{b}", View2)
  
  app = web.Application()
  app.router.add_view("/route-1/{a}", View1)
  app.add_subapp("/sub-app", sub_app)
  
  
  def make_app():
      app = web.Application()
      app.router.add_view("/route-3/{a}", View1)
      return app
  