    out_dicts[i][PREV_KEY] = (prev[0],) + (prev[i + 1],)
            else:
                out_dicts[i][PREV_KEY] = prev
        return out_dicts

    def __getitem__(self, i):
        &#34;&#34;&#34;Accesses ith item in the vfunc set&#34;&#34;&#34;
        return self.vfuncs[i]

    def __contains__(self, key):
        &#34;&#34;&#34;Returns true if vfuncs is a dict and key is one of its keys&#34;&#34;&#34;
        if isinstance(self.vfuncs, dict):
            return key in self.vfuncs.keys()
        retur