code: def collect_links(self, env=None):
          
          for asset in self.assets.values():
              if asset.has_bundles():
                  asset.collect_files()
          if env is None:
              env = self.config.env
          if env == static_bundle.ENV_PRODUCTION:
              self._minify(emulate=True)
          self._add_url_prefix()
docs: Return links without build files