I want to get an equivalent to `mean(..., na.rm = T)`

with `partial`

means.

Here is my example

```
a <- list(na.rm = TRUE)
purrr::partial(mean, !!!a)(c(1, NA, 3))
#> Error in !a: invalid argument type
purrr::partial(mean, !!!a)
#> function (...)
#> mean(!!!a, ...)
purrr::partial(...f = mean, ... = !!!a)(c(1, NA, 3))
#> [1] NA
purrr::partial(...f = mean, ... = !!!a)
#> function (...)
#> mean(... = !!!a, ...)
```

^{Created on 2019-02-01 by the reprex package (v0.2.1)}