How to see exception generated into django template variable?

Inside a Django template, one can call an object method like this :

{{ my_object.my_method }}

The problem is when you get an exception/bug in 'def my_method(self)', it is hidden when rendering the template (there is an empty string output instead, so no errors appears).

As I want to debug what's wrong in 'def my_method(self)', I would like to turn on something like a global django flag to receive such exception.

in settings.py, I already have

DEBUG = True 
TEMPLATE_DEBUG = True

I can receive many kind of template exceptions, but none when I trig an object method.

What can I do ?