Update RAID stats using the input method.

def update(self):
        """Update RAID stats using the input method."""
        # Init new stats
        stats = self.get_init_value()

        if import_error_tag:
            return self.stats

        if self.input_method == 'local':
            # Update stats using the PyMDstat lib (https://github.com/nicolargo/pymdstat)
            try:
                # Just for test
                # mds = MdStat(path='/home/nicolargo/dev/pymdstat/tests/mdstat.10')
                mds = MdStat()
                stats = mds.get_stats()['arrays']
            except Exception as e:
                logger.debug("Can not grab RAID stats (%s)" % e)
                return self.stats

        elif self.input_method == 'snmp':
            # Update stats using SNMP
            # No standard way for the moment...
            pass

        # Update the stats
        self.stats = stats

        return self.stats