Create node independent way of using calais module

calais_get_rdf() takes a node as parameter, there is no other function in calais module that takes content and returns calais' return values.

I am looking for a more generic API function. What about a basic

calais_get_rdf($content); 
// the strucuture of $content depends on what the calais API accepts. 
// e. g. if it accepts title, body, author, the $content variable should be an array that can hold title, body and or author. 

and a node specific

calais_get_rdf_node($node);