Hello wise monks!

I would like to use Getopt::Long module in to declare a flag which can get one string, many strings or none.
I know how to make each one separate, but I don't know how to do all of them.
For example:
GetOptions("flag=s{,}" => "$flag");

If I run "./perl_script.pl --flag" it will say that I didn't gave it a string.
How can I handle this case? I would like that the following code will work:

"./perl_script.pl --flag"
"./perl_script.pl --flag a"
"./perl_script.pl --flag a,b,c,d,e,f"

In reply to GetOptions getting a string by ovedpo15

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