code: def on_post(self, req, resp, rid):
          
  
          signals.pre_req.send(self.model)
          signals.pre_req_upload.send(self.model)
  
          props = req.deserialize(self.mimetypes)
          model = find(self.model, rid)
  
          signals.pre_upload.send(self.model, model=model)
  
          try:
              conn = s3_connect(self.key, self.secret)
              path = self._gen_s3_path(model, props)
              s3_url = s3_upload(self.acl, self.bucket, conn, props['content'],
                                 props['content-type'], path)
          except IOError:
              abort(ServiceUnavailable(**{
                  'detail': 'The upload attempt failed unexpectedly',
              }))
          else:
              signals.post_upload.send(self.model, model=model, url=s3_url)
  
              resp.location = s3_url
              resp.status = falcon.HTTP_201
  
              resp.serialize({'data': {'url': s3_url}})
  
              signals.post_req.send(self.model)
              signals.post_req_upload.send(self.model)
docs: Deserialize the file upload & save it to S3
  
          File uploads are associated with a model of some
          kind. Ensure the associating model exists first &
          foremost.