This method ensure keeping the cropr_simulation attribute when subsetting a
cropr_simulation list.
# S3 method for class 'cropr_simulation'
x[...]A subset of a cropr_simulation, keeping its attribute
if (FALSE) { # \dontrun{
library(SticsRFiles)
sim <- SticsRFiles::get_sim(workspace = "inst/extdata/stics_example_1")
sim[[1]] # returns a `cropr_simulation` list
} # }