Turn analysis code into a function

somewhere we have
``` r

mtcars |>
# TODO: turn into a function which uses the number of cyl as an arg
filter(cyl == 4) |>
ggplot(aes(x = wt)) +
geom_histogram()

```
this could be a function! :)

Locate the R code containing the mtcars pipeline, since the issue does not identify a file. Start by reviewing the existing filter and ggplot code; done means extracting it into a function that accepts the number of cylinders as an argument and preserves the histogram output.

Scritto dal modello di indicizzazione a partire dal testo della issue.