By default, a kpss test (via `feasts::unitroot_kpss()`

) will be performed
for testing the required first order differences, and a test of the seasonal
strength (via `feasts::feat_stl()`

seasonal_strength) being above the 0.64
threshold is used for determining seasonal required differences.

```
unitroot_options(
ndiffs_alpha = 0.05,
nsdiffs_alpha = 0.05,
ndiffs_pvalue = ~feasts::unitroot_kpss(.)["kpss_pvalue"],
nsdiffs_pvalue = ur_seasonal_strength(0.64)
)
```

- ndiffs_alpha, nsdiffs_alpha
The level for the test specified in the

`pval`

functions. As long as`pval < alpha`

, differences will be added.- ndiffs_pvalue, nsdiffs_pvalue
A function (or lambda expression) that provides a p-value for the unit root test. As long as

`pval < alpha`

, differences will be added.For the function for the seasonal p-value, the seasonal period will be provided as the

`.period`

argument to this function. A vector of data to test is available as`.`

or`.x`

.

A list of parameters