hing function. If None, defaults to self.vfuncs.

        Returns
        -------
        out_dict: dict
            Dictionary with items being determined by functions in vfunc set.
            Functions and input dictionaries are currently matched using a cartesian matching format.

        Examples
        --------
        &gt;&gt;&gt; vfuncs, data = {LR : logistic}, {train_1 : [X1,y1], train2 : [X2,y2]}
        {(train_1, LR) : fitted logistic, (train_2, LR) :  fitted logistic}
        &#34;&#34;&#34;
 