human
Complete this python program:
def bookmark():
assistant
#Here is the Python program you requested.

    """A CompletionModel filled with all bookmarks.
    """
    def delete(data):
        'Delete    a    bookmark    from    the    completion    menu.'
        urlstr = data[0]
        log.completion.debug('Deleting    bookmark    {}'.format(urlstr))
        bookmark_manager = objreg.get('bookmark-manager')
        bookmark_manager.delete(urlstr)
    model = completionmodel.CompletionModel(column_widths=(30, 70, 0))
    marks = objreg.get('bookmark-manager').marks.items()
    model.add_category(listcategory.ListCategory('Bookmarks', marks, delete_func=delete))
    return model