def METHOD_NAME(base, extra):
    """
    Merge two lists of options (strings in the form of name=value).
    Take everything from base and add properties from extra
    (according to names) that are not present in the base.
    :param base: list of properties
    :param extra: list of properties
    :return: merged list
    """
    extra_prop_names = set(map(lambda x: x.split('=')[0], base))
    ret = set(base)
    for item in extra:
        nv = item.split("=")
        if nv[0] not in extra_prop_names:
            ret.add(item)
    return list(ret)