def METHOD_NAME(s, arrayexprs: Optional[Set[str]] = None) -> Union[str, List[str]]:
    """ 
    Converts an array of symbolic variables (or one) to C++ strings. 
    :param s: Symbolic expression to convert.
    :param arrayexprs: Set of names of arrays, used to convert SymPy 
                       user-functions back to array expressions.
    :return: C++-compilable expression or list thereof.
    """
    if not isinstance(s, list):
        return _sym2cpp(s, None if arrayexprs is None else frozenset(arrayexprs))
    return [METHOD_NAME(d, arrayexprs) for d in s]