valuated lazily, i.e. outputs are `VfuncPromise`.

    Returns
    -------
    out_dict: dict
        Dictionary with items being determined by functions in vfunc set.
        Functions and input dictionaries are currently matched using cartesian matching format.
    &#34;&#34;&#34;
    for in_dict in args:
        if not isinstance(in_dict, dict):
            raise Exception(
                &#34;Run init_args on data before using it when calling a Vset!&#34;
            )

    data_dict = combine_dicts(*a