La${}_{2-x}$Ba${}_x$CuO${}_4$ ($x=\frac{1}{8}$) $\mu$SR data are inconsistent with spin stripe but consistent with spin spiral

I analyze available $\mu$SR data and show that it is inconsistent with the spin stripe but consistent with the coplanar spin spiral. The plane of the spiral coincides with the CuO${}_2$-plane. The static expectation value of the spin is $S=0.37\times \frac{1}{2}$.