Macro call with trailing comma?

Hi all,

The FreePBX dialplan has some marco calls with training commas like so:

Macro(dialout-trunk,1,${EXTEN:1},)

and

exten => _9.,n,Macro(record-enable,${AMPUSER},OUT,)

Is this meant to mean a variable list of arguments of just empty arguments? If one just passed in 1 argument when two were expected would that result in the other variable being null by default?

thanks