This is a simple wrapper around the `bs`

function in
the splines package. It will default to a spline with 10 degrees of
freedom.

`s(x, df, ...)`

x

The predictor value.

df

Degrees of freedom. Defaults to the minimum of 10 or one minus the number of unique values in x.

…

Arguments passed to the `bs`

function.

A predictor matrix of the basis functions.

This is a simple wrapper written as users may find it easier to simply type
`s`

rather than selecting parameters for a spline. We also include
`predict`

and `makepredictcall`

generic functions for the class
so it will work in settings where `predict`

is called.