How to use the ocrd.WorkspaceBackupManager function in ocrd

def workspace_backup_add(ctx):
    """
    Create a new backup
    """
    backup_manager = WorkspaceBackupManager(Workspace(ctx.resolver, directory=ctx.directory, mets_basename=ctx.mets_basename, automatic_backup=ctx.automatic_backup))
    backup_manager.add()

def workspace_backup_undo(ctx):
    """
    Restore the last backup
    """
    backup_manager = WorkspaceBackupManager(Workspace(ctx.resolver, directory=ctx.directory, mets_basename=ctx.mets_basename, automatic_backup=ctx.automatic_backup))
    backup_manager.undo()

def workspace_backup_restore(ctx, choose_first, bak):
    """
    Restore backup BAK
    """
    backup_manager = WorkspaceBackupManager(Workspace(ctx.resolver, directory=ctx.directory, mets_basename=ctx.mets_basename, automatic_backup=ctx.automatic_backup))
    backup_manager.restore(bak, choose_first)

def workspace_backup_list(ctx):
    """
    List backups
    """
    backup_manager = WorkspaceBackupManager(Workspace(ctx.resolver, directory=ctx.directory, mets_basename=ctx.mets_basename, automatic_backup=ctx.automatic_backup))
    for b in backup_manager.list():
        print(b)