How to export to markdown programmatically without the table of contents?

[Marcin Borkowski]

Hi fellow Orgers,

I'd like to export a Org-mode formatted string to markdown, but without
the table of contents.

(org-export-string-as my-string 'md t '(toc nil))

didn't work (the ToC was still there).  What am I missing?

TIA,

-- 
Marcin Borkowski
http://mbork.pl