@Override
  public void update(@NotNull AnActionEvent e) {
    final VcsKey vcsKey = e.getData(VcsDataKeys.VCS);
    final boolean isSvn = SvnVcs.getKey().equals(vcsKey);
    e.getPresentation().setVisible(isSvn);
    final VcsFileRevision revision = e.getData(VcsDataKeys.VCS_FILE_REVISION);
    e.getPresentation().setEnabled(isSvn && revision != null);
  }
@Override
  public void update(@NotNull AnActionEvent e)