List instance info.

def get(self, instance_ids=None, filters=None):
        """List instance info."""
        params = {}
        if filters:
            params["filters"] = make_filters(filters)
        if instance_ids:
            params['InstanceIds'] = instance_ids
        reservations = self.call("DescribeInstances",
                                 response_data_key="Reservations",
                                 **params)
        if reservations:
            return list(chain(*(r["Instances"] for r in reservations)))
        return []