Log (DEBUG) the result of the function fct.

def _log_result_decorator(fct):
        """Log (DEBUG) the result of the function fct."""
        def wrapper(*args, **kw):
            ret = fct(*args, **kw)
            logger.debug("%s %s %s return %s" % (
                args[0].__class__.__name__,
                args[0].__class__.__module__[len('glances_'):],
                fct.__name__, ret))
            return ret
        return wrapper