code: @Override
      public boolean isPackageInstaller(final String packageName) {
          Logger.d("sPackageInstaller: packageName = ", packageName);
  
          final PackageManager packageManager = context.getPackageManager();
          final String installerPackageName = packageManager.getInstallerPackageName(packageName);
  
          Logger.d("installerPackageName = ", installerPackageName);
  
          return NOKIA_INSTALLER.equals(installerPackageName);
      }
docs: Returns true only if actual installer for specified app