Construct SpaceGroupTransformation from its transformation string.
        :param P: matrix
        :param p: origin shift vector
        :return:

def from_transformation_string(cls, transformation_string="a,b,c;0,0,0"):
        """
        Construct SpaceGroupTransformation from its transformation string.
        :param P: matrix
        :param p: origin shift vector
        :return:
        """
        P, p = JonesFaithfulTransformation.parse_transformation_string(
            transformation_string)
        return cls(P, p)