code: def addonModules(cls, recurse=True):
          
          prop = '_{0}__addon_modules'.format(cls.__name__)
          out = set()
  
          # lookup base classes
          if recurse:
              for base in cls.__bases__:
                  if issubclass(base, AddonManager):
                      out.update(base.addonModules(recurse))
  
          # always use the highest level for any given key
          out.update(getattr(cls, prop, set()))
          return out
docs: Returns all the modules that this addon class uses to load plugins
          from.
          
          :param      recurse | <bool>
          
          :return     [<str> || <module>, ..]