code: public static String customScopeCollectionToString(@NonNull Collection<String> scopes) {
          return TextUtils.join(" ", scopes).toLowerCase();
      }
docs: Converts a {@link Collection} of {@link String}s into a space-delimited {@link String}.
  
  @param scopes the {@link Collection} of {@link String}s to convert
  @return a space-delimited {@link String} of {@link Scope}s