def set_to_default(section, key):
    """Set the value of the given seciton and key to default

    :param section: the section of a configspec
    :type section: section
    :param key: a key of the section
    :type key: str
    :returns: None
    :raises: None
    """
    section[key] = section.default_values.get(key, section[key])