Helper param as array(list)

[EuroZond]

Hello! I do not understand how i can use list as param in helper? So i have some helper ex:

$this->_dust->helpers['print_r'] = function...
~~template.dust~~
{@print_r dump=... /}

How i can transmit into the dump list|array ?

dump[1]="100" dump["key"]="100" dump[]="100" dump.key="100" dump=["key":data.reference]

I try it all. Please help. I cant find any ex. about it.