Update defaults after a change in version

def _update_defaults(self, defaults, old_version, verbose=False):
        """Update defaults after a change in version"""
        old_defaults = self._load_old_defaults(old_version)
        for section, options in defaults:
            for option in options:
                new_value = options[ option ]
                try:
                    old_value = old_defaults.get(section, option)
                except (cp.NoSectionError, cp.NoOptionError):
                    old_value = None
                if old_value is None or \
                  to_text_string(new_value) != old_value:
                    self._set(section, option, new_value, verbose)