Avoid "JRE required" msg upon extension installation

I developed a LibreOffice Extension that contains a Python macro (and 
the required Python libs):

https://github.com/akretion/factur-x-libreoffice-extension  file 
"factur-x_macro.oxt" (source code in "extension/" subdir)

But, when I add this extension to LibreOffice on a PC without Java 
installed, I get this error message:

<< LibreOffice requires a Java runtime environment (JRE) to perform this 
task. However, use of a JRE has been disabled. Do you want to enable the 
use of a JRE now?  >>

If I answer "No", the extension will still work fine (because the 
extension doesn't need Java at all, it only contains a Python macro). So 
this message is wrong.

Could I change something in my macro to avoid this message ? My 
extension targets users without IT background and they could be scared 
by that wrong message.

Thanks in advance for your help,

--
Alexis de Lattre