Scrapy + django-item + postgresql (sqlalchemy), how to map a class?

Question

PostgreSQL

I use this stack in a project. The following error is thrown:

sqlalchemy.orm.exc.UnmappedInstanceError: Class news_scrap.items.NewsItem' is not mapped.

It seems that I understand what's wrong, but how to fix it, I'll never know. The Internet tells you how to work if you do not have django-item, and with it - xs. I hope for you. Below are the scrapy files.
Items.py

from scrapy_djangoitem import DjangoItem
from main.models import News

class NewsItem(DjangoItem):
    django_model = News
    __tablename__ = "main_news"

Models.py

from sqlalchemy import *
from sqlalchemy.engine.url import URL
from . import settings

def db_connect():
    """
    Performs database connection using database settings from settings.py.
    Returns sqlalchemy engine instance
    """
    return create_engine(URL(**settings.DATABASE))

Pipelines.py

from sqlalchemy.orm import sessionmaker
from .items import NewsItem
from .models import db_connect

class NewsScrapPipeline(object):
    def __init__(self):
        """
        Initializes database connection and sessionmaker.
        Creates deals table.
        """
        #log.INFO('First Point')
        engine = db_connect()
        self.Session = sessionmaker(bind=engine)

    def process_item(self, item, spider):

        session = self.Session()
        news = NewsItem(**item)
        #log.INFO('This Point')

        try:
            session.add(news)
            session.commit()
        except:
            session.rollback()
            raise
        finally:
            session.close()

        return item

If you need any more plots when, say.