### How to solve an equation over finite field?

I would like to solve an equation like

```
solve( ((k^2)%17)==8,k)
```

or

```
R = GF(17)
solve(R(k)^2==8,k)
```

or as math equation: $k^2 \equiv 8 \mod 17$

This would be true for e.g. $k=5$

If I use the solve function above in sagemath I get an empty result $[]$ for first and 'self must be a numeric expression' for second.

How can I solve such equation?