string? interpretation_for_mimetype (string? mimetype)
        string? interpretation_for_mimetype (string? mimetype)
        zeitgeist_interpretation_for_mimetype:
Look up the subject interpretation type associated with @mimetype.
| mimetype | A MIME-type string. Eg. text/plain | 
| A URI defining the subject interpretation type associated with "mimetype" or %NULL in case "mimetype" is unknown |