How to use the @storefront-api/lib/cache-instance.get function in @storefront-api/lib

resultProcessor.process(_resBody.hits.hits).then((result) => {
            _resBody.hits.hits = result
            _cacheStorageHandler(config, _resBody, reqHash, tagsArray)
            res.json(_resBody);
          }).catch((err) => {
            console.error(err)
          })
        }
      } else { // no cache storage if no results from Elastic
        res.json(_resBody);
      }
    });
  }

  if (config.server.useOutputCache && cache) {
    cache.get(
      'api:' + reqHash
    ).then(output => {
      if (output !== null) {
        res.setHeader('X-VS-Cache', 'Hit')
        res.json(output)
        console.log(`cache hit [${req.url}], cached request: ${Date.now() - s}ms`)
      } else {
        res.setHeader('X-VS-Cache', 'Miss')
        console.log(`cache miss [${req.url}], request: ${Date.now() - s}ms`)
        dynamicRequestHandler()
      }
    }).catch(err => console.error(err))
  } else {
    dynamicRequestHandler()
  }
}