specifying multiple node types in an argument

How can I specify multiple node types in an argument (in this case to output an addthis banner only on specific node type pages)?

I succeeded in specifying this for a single node type by changing this line in the module code:

if ($type === 'node' && user_access('view addthis'))
to:
if ($type === 'node' && ($node->type == "website")

I then tried this code to specify two node types:

if ($type === 'node' && (array($node->type, array("website", "portals"))

But the result is that the banner is output on the pages of all my node types and not just the two I specified in the code.

I am not a coder and I have the feeling I am overlooking something basic in defining the array here but what?

Thanks for any help,
Gerben