docs: def add_config_options(self):
          """ You can override this method in order to add your options to the
          config object."""
          # default section
          default = self.config.get_default_section()
          default.add_element(
              Element('debug',
                      e_type=int,
                      e_type_exclude=True,
                      default=0,
                      desc="""debug level : default : 0."""))