code: function findAll() {
    return jp.dataDirs({ withSysPrefix: true }).then(dirs => {
      return Promise.all(dirs
        // get kernel infos for each directory and ignore errors
        .map(dir => getKernelInfos(path.join(dir, 'kernels')).catch(() => {}))
      ).then(extractKernelResources)
    });
  }
docs: Get an array of kernelResources objects for the host environment
  This matches the Jupyter notebook API for kernelspecs exactly
  @return {Promise<Object<string,kernelResource>} Promise for an array of kernelResources objects