Expected behaviour of text:groups

[pgleghorn]

Hi, for this function call

text:groups("12345,67890", "([0-9][0-9][0-9][0-9][0-9])")

I would expect a sequence of length three

"12345,67890"
"12345"
"67890"

but the result is

"12345,67890"
"12345"

am I misunderstanding the function?
Thanks,
Phil