How to use the ara.models.db.session.add function in ara

def close_task(self):
        """
        Marks the completion time of the currently active task.
        """
        if self.task is not None:
            log.debug('Closing task %s (%s)',
                      self.task.name,
                      self.task.id)
            self.task.stop()
            db.session.add(self.task)
            db.session.commit()

            self.task = None
            self.loop_items = []

self.taskresult = models.TaskResult(
            task=self.task,
            host=host,
            time_start=result.task_start,
            time_end=result.task_end,
            result=jsonutils.dumps(results),
            status=status,
            changed=result._result.get('changed', False),
            failed=result._result.get('failed', False),
            skipped=result._result.get('skipped', False),
            unreachable=result._result.get('unreachable', False),
            ignore_errors=kwargs.get('ignore_errors', False),
        )

        db.session.add(self.taskresult)
        db.session.commit()

        if self.task.action == 'setup' and 'ansible_facts' in result._result:
            values = jsonutils.dumps(result._result['ansible_facts'])
            facts = models.HostFacts(values=values)
            host.facts = facts

            db.session.add(facts)
            db.session.commit()

def get_or_create_file(self, path):
        try:
            if self.playbook.id:
                file_ = (models.File.query
                         .filter_by(path=path)
                         .filter_by(playbook_id=self.playbook.id)
                         .one())
                return file_
        except models.NoResultFound:
            pass

        file_ = models.File(path=path, playbook=self.playbook)
        db.session.add(file_)
        db.session.commit()

        try:
            with open(path, 'r') as fd:
                data = fd.read()
            sha1 = models.content_sha1(data)
            content = models.FileContent.query.get(sha1)

            if content is None:
                content = models.FileContent(content=data)

            file_.content = content
        except IOError:
            LOG.warn('failed to open %s for reading', path)

        return file_

def get_or_create_host(self, hostname):
        try:
            host = (models.Host.query
                    .filter_by(name=hostname)
                    .filter_by(playbook_id=self.playbook.id)
                    .one())
        except models.NoResultFound:
            host = models.Host(name=hostname, playbook=self.playbook)
            db.session.add(host)
            db.session.commit()

        return host

def create_or_update_key(self, playbook_id, key, value, type):
        try:
            data = (models.Data.query
                    .filter_by(key=key)
                    .filter_by(playbook_id=playbook_id)
                    .one())
            data.value = value
            data.type = type
        except models.NoResultFound:
            data = models.Data(playbook_id=playbook_id,
                               key=key,
                               value=value,
                               type=type)
        db.session.add(data)
        db.session.commit()

        return data

def close_playbook(self):
        """
        Marks the completion time of the currently active playbook.
        """
        if self.playbook is not None:
            log.debug('Closing playbook %s', self.playbook.path)
            self.playbook.stop()
            self.playbook.complete = True
            db.session.add(self.playbook)
            db.session.commit()

self.taskresult = models.TaskResult(
            task=self.task,
            host=host,
            time_start=result.task_start,
            time_end=result.task_end,
            result=jsonutils.dumps(results),
            status=status,
            changed=result._result.get('changed', False),
            failed=result._result.get('failed', False),
            skipped=result._result.get('skipped', False),
            unreachable=result._result.get('unreachable', False),
            ignore_errors=ignore_errors,
        )

        db.session.add(self.taskresult)
        db.session.commit()

def create_or_update_key(self, playbook_id, key, value, type):
        try:
            data = (models.Data.query
                    .filter_by(key=key)
                    .filter_by(playbook_id=playbook_id)
                    .one())
            data.value = value
            data.type = type
        except models.NoResultFound:
            data = models.Data(playbook_id=playbook_id,
                               key=key,
                               value=value,
                               type=type)
        db.session.add(data)
        db.session.commit()

        return data