def set_implicit_options(role_fn):
    """
    Add customization options to role functions, unless explicitly set or
    disabled.
    """
    if not hasattr(role_fn, 'options') or role_fn.options is None:
        role_fn.options = {'class': directives.class_option}
    elif 'class' not in role_fn.options:
        role_fn.options['class'] = directives.class_option
dataset/ETHPy150Open adieu/allbuttonspressed/docutils/parsers/rst/roles.py/set_implicit_options/original