Crash in get_hydrometrie_observations_tr for empty response

See reproducible example below:

library(hubeau)
params <- list(code_entite = "H0203020",
               date_debut_obs = format(Sys.Date()-3),
               grandeur_hydro = "Q")
df <- get_hydrometrie_observations_tr(params, entities = "wrong value")

The function crashes with this error message:

Error in l[sapply(l, is.null)] <- NULL : invalid subscript type 'list'