What calculate $\mathrm{ln}i$

I would like to know how to calculate $\mathrm{ln}i$. I found a formula on the internet that says

$\mathrm{ln}z=\mathrm{ln}|z|+i\mathrm{Arg}(z)$

Then $|i|=1$ and $\mathrm{Arg}(i)$ is?

I would like to know how to calculate $\mathrm{ln}i$. I found a formula on the internet that says

$\mathrm{ln}z=\mathrm{ln}|z|+i\mathrm{Arg}(z)$

Then $|i|=1$ and $\mathrm{Arg}(i)$ is?