Creates the internal transformer that maps the cluster center's high
        dimensional space to its two dimensional space.

def transformer(self):
        """
        Creates the internal transformer that maps the cluster center's high
        dimensional space to its two dimensional space.
        """
        ttype = self.embedding.lower() # transformer method type

        if ttype == 'mds':
            return MDS(n_components=2, random_state=self.random_state)

        if ttype == 'tsne':
            return TSNE(n_components=2, random_state=self.random_state)

        raise YellowbrickValueError("unknown embedding '{}'".format(ttype))