Invalid Argument in foreach Loop

I am getting the following error:

Warning: Invalid argument supplied for foreach() in conditional_styles_preprocess_html() (line 14 of /sites/all/modules/conditional_styles/conditional_styles.module).

The line is:
foreach ($themes[$key]->info['stylesheets-conditional'][$condition][$media] as $stylesheet) {

I believe it should be:
foreach (array_keys($themes[$key]->info['stylesheets-conditional'][$condition][$media]) as $stylesheet) {

I am brand new to Drupal so that may not be correct, although it does seem to make the error disappear.