If 'referenceable_types' is not an array, it results in a warning indicating an invalid argument supplied for "foreach()"

Full Error:
warning: Invalid argument supplied for foreach() in .../wwwroot/sites/all/modules/cnr/corresponding_node_references.module on line 53.

The line:

foreach ($data['referenceable_types'] as $reference) {

I was able to temporarily fix this by wrapping the foreach loop in an if statement

if (is_array($data['referenceable_types'])) {
foreach ($data['referenceable_types'] as $reference) {
....
}
}


Cheers.