Help with source("w1_nb4_source_code.R") # load external SIR modelling code

I found this code that works on the page where I found it but on my local computer it gives an error that the file can not be found. is anyone familiar with this “source(“w1_nb4_source_code.R”)” part

Warning message in file(filename, “r”, encoding = encoding): “cannot open file ‘w1_nb4_source_code.R’: No such file or directory”

Error in file(filename, “r”, encoding = encoding): cannot open the connection Traceback:

source(“w1_nb4_source_code.R”) # load external SIR modelling code
par(mfrow = c(2,2)) # Show 2*2 separate plots in one page

(2 rows, 2 per row)

run_sir_model(beta = 0.1, gamma = 0.1, duration = 365)
run_sir_model(beta = 0.2, gamma = 0.1, duration = 365)
run_sir_model(beta = 0.7, gamma = 0.1, duration = 60)
run_sir_model(beta = 1.5, gamma = 0.1, duration = 60)
run_sir_model(beta = 1.0, gamma = 0.1, duration = 60)