for this I thinnk you sould use extra render.
{{text = "`` here is my code ``:pre_with_code"}}
{{=MARKMIN(text, extra={"pre_with_code": lambda text:
"<pre><code>{0}</code></pre>".format(text)})}}
Tested on shell
In [4]: text = "`` here is my code ``:pre_with_code"
In [5]: print MARKMIN(text, extra={"pre_with_code": lambda text:
"<pre><code>{0}</code></pre>".format(text)})
<pre><code> here is my code </code></pre>
--

