protected static @NotNull String stringifyBranchesByRepos(@NotNull Map<GitRepository, String> heads) {
    MultiMap<String, VirtualFile> grouped = groupByBranches(heads);
    if (grouped.size() == 1) {
      return grouped.keySet().iterator().next();
    }
    return StringUtil.join(grouped.entrySet(), entry -> {
      String roots = StringUtil.join(entry.getValue(), file -> file.getName(), ", ");
      return GitBundle.message("branch.operation.in", entry.getKey(), roots);
    }, UIUtil.BR);
  }
protected static @NotNull String stringifyBranchesByRepos(@NotNull Map<GitRepository, String> heads)