old_contents: """
  byceps.services.shop.order.ordered_articles_service
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  :Copyright: 2006-2018 Jochen Kupperschmidt
  :License: Modified BSD, see LICENSE for details.
  """
  
  from collections import Counter
  from typing import Dict, Sequence
  
  from ....database import db
  
  from ..article.models.article import ArticleNumber
  
  from .models.order_item import OrderItem
  from .models.payment import PaymentState
  
  
  def count_ordered_articles(article_number: ArticleNumber
                            ) -> Dict[PaymentState, int]:
      """Count how often the article has been ordered, grouped by the
      order's payment state.
      """
      order_items = OrderItem.query \
          .filter_by(article_number=article_number) \
          .options(
              db.joinedload('order'),
              db.joinedload('article'),
          ) \
          .all()
  
      # Ensure every payment state is present in the resulting dictionary,
      # even if no orders of the corresponding payment state exist for the
      # article.
      counter = Counter({state: 0 for state in PaymentState})
  
      for order_item in order_items:
          counter[order_item.order.payment_state] += order_item.quantity
  
      return dict(counter)
  
  
  def get_order_items_for_article(article_number: ArticleNumber
                                 ) -> Sequence[OrderItem]:
      """Return all order items for that article."""
      return OrderItem.query \
          .filter_by(article_number=article_number) \
          .all()
  
new_contents: """
  byceps.services.shop.order.ordered_articles_service
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
  :Copyright: 2006-2018 Jochen Kupperschmidt
  :License: Modified BSD, see LICENSE for details.
  """
  
  from collections import Counter
  from typing import Dict, Sequence
  
  from ....database import db
  
  from ..article.models.article import ArticleNumber
  
  from .models.order_item import OrderItem, OrderItemTuple
  from .models.payment import PaymentState
  
  
  def count_ordered_articles(article_number: ArticleNumber
                            ) -> Dict[PaymentState, int]:
      """Count how often the article has been ordered, grouped by the
      order's payment state.
      """
      order_items = OrderItem.query \
          .filter_by(article_number=article_number) \
          .options(
              db.joinedload('order'),
              db.joinedload('article'),
          ) \
          .all()
  
      # Ensure every payment state is present in the resulting dictionary,
      # even if no orders of the corresponding payment state exist for the
      # article.
      counter = Counter({state: 0 for state in PaymentState})
  
      for order_item in order_items:
          counter[order_item.order.payment_state] += order_item.quantity
  
      return dict(counter)
  
  
  def get_order_items_for_article(article_number: ArticleNumber
                                 ) -> Sequence[OrderItemTuple]:
      """Return all order items for that article."""
      order_items = OrderItem.query \
          .filter_by(article_number=article_number) \
          .all()
  
      return [item.to_tuple() for item in order_items]
  
subject: Return `OrderItemTuple`s rather than order item database entities from service