scalar  : B_FOLD_START scalar_group B_FOLD_END

def p_scalar__folded(self, p):
        """
        scalar  : B_FOLD_START scalar_group B_FOLD_END
        """
        scalar_group = ''.join(p[2])
        folded_scalar = fold(dedent(scalar_group)).rstrip()
        p[0] = ScalarDispatch('%s\n' % folded_scalar, cast='str')