Overwrite the default export method.

        - Only exports containers
        - The key is the first container name

def get_export(self):
        """Overwrite the default export method.

        - Only exports containers
        - The key is the first container name
        """
        ret = []
        try:
            ret = self.stats['containers']
        except KeyError as e:
            logger.debug("docker plugin - Docker export error {}".format(e))
        return ret