These are iso-year-week-day methods for the arithmetic generics.

You cannot add weeks or days to an iso-year-week-day calendar. Adding
days is much more efficiently done by converting to a time point first
by using `as_naive_time()`

or `as_sys_time()`

. Adding weeks is equally
as efficient as adding 7 days. Additionally, adding weeks to an invalid
iso-year-week object containing `iso_year_week_day(2019, 53)`

would be
undefined, as the 53rd ISO week of 2019 doesn't exist to begin with.

## Usage

```
# S3 method for clock_iso_year_week_day
add_years(x, n, ...)
```

## Arguments

- x
`[clock_iso_year_week_day]`

A iso-year-week-day vector.

- n
`[integer / clock_duration]`

An integer vector to be converted to a duration, or a duration corresponding to the arithmetic function being used. This corresponds to the number of duration units to add.

`n`

may be negative to subtract units of duration.- ...
These dots are for future extensions and must be empty.

## Examples

```
x <- iso_year_week_day(2019, 1, 1)
add_years(x, 1:2)
#> <iso_year_week_day<day>[2]>
#> [1] "2020-W01-1" "2021-W01-1"
```