two functions from different packages not working together - r

Question

So I am doing work on ruin probability. I am performing monte-carlo simulations through R. The package that works perfectly for this is 'ruin'. You simply specify inputs for different ruin models. I am trying to simulate a SparreAndersen model where there are two random variable generators from different distributions. Typical distributions such as exponential or gamma work fine, using rgamma or rexp.
The problem that I am having is that I require a mixed exponential function as one of the r.v. generators. I found a great package that achieves this, called 'gendist' where I use the rmixt function to generate r.v.s from a mixed exponential function.
Running rmixt with all parameters works fine, giving a correct and accurate numerical output.
Running rexp with all parameters works fine, giving a correct and accurate numerical output.
Running a SparreAndersen() function works fine when using any function that is NOT the rmixt function.
The problem: SparreAndersen does not like to use rmixt from 'gendist' package as a r.v. generator
When I try to run this function, I get this as an error
I have no idea why this isn't working???
See my entire code below:
library(ruin)
library(gendist)
rmixt(1, phi=1, spec1="exp", arg1=list(rate=3), spec2="exp",
arg2=list(rate=7) )
rexp(1, rate=1)
modelSA <- SparreAndersen(initial_capital = 1,
premium_rate = 5,
claim_interarrival_generator = rmixt,
claim_interarrival_parameters = list(1, phi=1, spec1="exp", arg1=list(rate=3), spec2="exp", arg2=list(rate=7)),
claim_size_generator = rexp,
claim_size_parameters = list(rate=1))
edit: I have found a working solution, not involving the 'gendist' package. Let me know if this is the best way to go about doing this.
My new working code:
# Function which generates multiple exponential
rmixedexp <- function(...) {
choice <- c(...)
return(rexp(n=1, sample(choice, 1, replace=TRUE)))
}
modelSA <- SparreAndersen(initial_capital = 5,
premium_rate = 5,
claim_interarrival_generator = rmixedexp,
claim_interarrival_parameters = list(1, 3, 7),
claim_size_generator = rexp,
claim_size_parameters = list(rate=1))
I had to make my own function which takes any number of parameters, for example, 2. Each parameter is the rate of the exponential, chosen randomly (probability half).