Takes a Lattice object and transforms it.
        :param lattice: Lattice
        :return:

def transform_lattice(self, lattice):
        # type: (Lattice) -> Lattice
        """
        Takes a Lattice object and transforms it.
        :param lattice: Lattice
        :return: 
        """
        return Lattice(np.matmul(lattice.matrix, self.P))