Get command-specific statistics from redis' INFO COMMANDSTATS command

def _check_command_stats(self, conn, tags):
        """Get command-specific statistics from redis' INFO COMMANDSTATS command
        """
        try:
            command_stats = conn.info("commandstats")
        except Exception:
            self.warning('Could not retrieve command stats from Redis. INFO COMMANDSTATS only works with Redis >= 2.6.')
            return

        for key, stats in iteritems(command_stats):
            command = key.split('_', 1)[1]
            command_tags = tags + ['command:{}'.format(command)]

            # When `host:` is passed as a command, `calls` ends up having a leading `:`
            # see https://github.com/DataDog/integrations-core/issues/839
            calls = stats.get('calls') if command != 'host' else stats.get(':calls')

            self.gauge('redis.command.calls', calls, tags=command_tags)
            self.gauge('redis.command.usec_per_call', stats['usec_per_call'], tags=command_tags)