def get_stats(self):
        """
        It returns a name and a value pairs of control files
        which are categorised in the stats group.
        """
        stats = {}
        for name, cls in self.stats.items():
            path = self.paths[name]
            if os.path.exists(path):
                try:
                    stats[name] = self._PARSERS[cls](fileops.read(path))
                except IOError as e:
                    # XXX: we have to distinguish unexpected errors from the expected ones
                    if e.errno == errno.EOPNOTSUPP:
                        # Since 3.5 memory.memsw.* are always created even if disabled.
                        # If disabled we will get EOPNOTSUPP when read or write them.
                        # See commit af36f906c0f4c2ffa0482ecdf856a33dc88ae8c5 of the kernel.
                        pass
                    if e.errno == errno.EIO:
                        # memory.kmem.slabinfo throws EIO until limit_in_bytes is set.
                        pass
                    else:
                        raise
        return stats
It returns a name and a value pairs of control files
        which are categorised in the stats group.