How to use the taguette.database.Tag function in taguette

return self.render('project_new.html',
                               name=name, description=description,
                               error="Please enter a name")

        # Create project
        project = database.Project(name=name, description=description)
        self.db.add(project)
        # Add user as admin
        membership = database.ProjectMember(
            project=project,
            user_login=self.current_user,
            privileges=database.Privileges.ADMIN
        )
        self.db.add(membership)
        # Add default set of tags
        self.db.add(database.Tag(project=project, path='interesting',
                                 description="Further review required"))
        self.db.add(database.Tag(project=project, path='people',
                                 description="Known people"))

        self.db.commit()
        self.redirect(self.reverse_url('project', project.id))

try:
            validate.project_name(name)
            validate.project_description(description)

            # Create project
            project = database.Project(name=name, description=description)
            self.db.add(project)
            # Add user as admin
            membership = database.ProjectMember(
                project=project,
                user_login=self.current_user,
                privileges=database.Privileges.ADMIN
            )
            self.db.add(membership)
            # Add default tags
            self.db.add(database.Tag(
                project=project,
                # TRANSLATORS: Default tag name
                path=self.gettext("interesting"),
                # TRANSLATORS: Default tag description
                description=self.gettext("Further review required")),
            )

            self.db.commit()
            return self.redirect(self.reverse_url('project', project.id))
        except validate.InvalidFormat as e:
            logger.info("Error validating ProjectAdd: %r", e)
            return self.render('project_new.html',
                               name=name, description=description,
                               error=self.gettext(e.message))

error="Please enter a name")

        # Create project
        project = database.Project(name=name, description=description)
        self.db.add(project)
        # Add user as admin
        membership = database.ProjectMember(
            project=project,
            user_login=self.current_user,
            privileges=database.Privileges.ADMIN
        )
        self.db.add(membership)
        # Add default set of tags
        self.db.add(database.Tag(project=project, path='interesting',
                                 description="Further review required"))
        self.db.add(database.Tag(project=project, path='people',
                                 description="Known people"))

        self.db.commit()
        self.redirect(self.reverse_url('project', project.id))

def post(self, project_id):
        obj = self.get_json()
        project = self.get_project(project_id)
        tag = database.Tag(project=project,
                           path=obj['path'], description=obj['description'])
        try:
            self.db.add(tag)
            self.db.flush()  # Need to flush to get tag.id
        except IntegrityError:
            self.db.rollback()
            self.set_status(409)
            return self.finish()
        cmd = database.Command.tag_add(
            self.current_user,
            tag,
        )
        self.db.add(cmd)
        self.db.commit()
        self.db.refresh(cmd)
        self.application.notify_project(project.id, cmd)

def post(self, project_id):
        project, privileges = self.get_project(project_id)
        if not privileges.can_add_tag():
            self.set_status(403)
            return self.send_json({'error': "Unauthorized"})
        try:
            obj = self.get_json()
            validate.tag_path(obj['path'])
            validate.tag_description(obj['description'])
            tag = database.Tag(project=project,
                               path=obj['path'],
                               description=obj['description'])
            try:
                self.db.add(tag)
                self.db.flush()  # Need to flush to get tag.id
            except IntegrityError:
                self.db.rollback()
                self.set_status(409)
                return self.finish()
            cmd = database.Command.tag_add(
                self.current_user,
                tag,
            )
            self.db.add(cmd)
            self.db.commit()
            self.db.refresh(cmd)

def get_highlights_for_export(self, project_id, path):
        project, _ = self.get_project(project_id)

        if path:
            tag = aliased(database.Tag)
            hltag = aliased(database.HighlightTag)
            highlights = (
                self.db.query(database.Highlight)
                .options(joinedload(database.Highlight.document))
                .join(hltag, hltag.highlight_id == database.Highlight.id)
                .join(tag, hltag.tag_id == tag.id)
                .filter(tag.path.startswith(path))
                .filter(tag.project == project)
                .order_by(database.Highlight.document_id,
                          database.Highlight.start_offset)
            ).all()
            name = None
        else:
            # Special case to select all highlights: we also need to select
            # highlights that have no tag at all
            document = aliased(database.Document)

sheet = workbook.add_worksheet('highlights')

            header = workbook.add_format({'bold': True})

            sheet.write(0, 0, 'id', header)
            sheet.write(0, 1, 'document', header)
            sheet.write(0, 2, 'tag', header)
            sheet.write(0, 3, 'content', header)
            sheet.set_column(0, 0, 5.0)
            sheet.set_column(1, 1, 15.0)
            sheet.set_column(2, 2, 15.0)
            sheet.set_column(3, 3, 80.0)
            row = 1
            for hl in highlights:
                tags = hl.tags
                assert all(isinstance(t, database.Tag) for t in tags)
                if tags:
                    tags = [t.path for t in tags]
                else:
                    tags = ['']
                for tag_path in tags:
                    sheet.write(row, 0, str(hl.id))
                    sheet.write(row, 1, hl.document.name)
                    sheet.write(row, 2, tag_path)
                    sheet.write(row, 3, convert.html_to_plaintext(hl.snippet))
                    row += 1
            workbook.close()
            with open(filename, 'rb') as fp:
                chunk = fp.read(4096)
                self.write(chunk)
                while len(chunk) == 4096:
                    chunk = fp.read(4096)

highlight_id = Column(Integer, ForeignKey('highlights.id',
                                              ondelete='CASCADE'),
                          primary_key=True)
    highlight = relationship('Highlight')
    tag_id = Column(Integer, ForeignKey('tags.id',
                                        ondelete='CASCADE'),
                    primary_key=True)
    tag = relationship('Tag')


Tag.highlights_count = column_property(
    select(
        [functions.count(HighlightTag.highlight_id)],
    ).where(
        HighlightTag.tag_id == Tag.id,
    ).correlate_except(HighlightTag)
)


def connect(db_url):
    """Connect to the database using an environment variable.
    """
    logger.info("Connecting to SQL database %r", db_url)
    kwargs = {}
    if db_url.startswith('sqlite:'):
        kwargs['connect_args'] = {'check_same_thread': False}
    engine = create_engine(db_url, **kwargs)
    # logging.getLogger('sqlalchemy.engine').setLevel(logging.INFO)

    if db_url.startswith('sqlite:'):
        @sqlalchemy.event.listens_for(sqlalchemy.engine.Engine, "connect")

def post(self, project_id, tag_id):
        project, privileges = self.get_project(project_id)
        if not privileges.can_update_tag():
            self.set_status(403)
            return self.send_json({'error': "Unauthorized"})
        try:
            obj = self.get_json()
            tag = self.db.query(database.Tag).get(int(tag_id))
            if tag is None or tag.project_id != project.id:
                self.set_status(404)
                return self.send_json({'error': "No such tag"})
            if obj:
                if 'path' in obj:
                    validate.tag_path(obj['path'])
                    tag.path = obj['path']
                if 'description' in obj:
                    validate.tag_description(obj['description'])
                    tag.description = obj['description']
                cmd = database.Command.tag_add(
                    self.current_user,
                    tag,
                )
                try:
                    self.db.add(cmd)

def tag_add(cls, user_login, tag):
        assert isinstance(tag, Tag)
        return cls(
            user_login=user_login,
            project_id=tag.project_id,
            payload={'type': 'tag_add',  # keep in sync above
                     'id': tag.id,
                     'path': tag.path,
                     'description': tag.description},
        )