Code folding in Sublime Text

[Mondata]

Sublime Text automatically adds a fold/unfold block when detecting commands like:
if
while
def
try

I´d like to override this behaviour and define my own set of characters for folding/unfolding.
Exactly, I want #+ to indicate the beginning of a folding block and #- to indicate the end.

Is there a (not to complicated) way of achieving this in this editor?

Many thanks.