has added Co-Op chain. Extendability to other chain has significantly improved as well.

supermarket_chain.py

@@ -0,0 +1,80 @@
+from abc import abstractmethod
+from enum import Enum
+from argparse import ArgumentTypeError
+from typing import Dict, List
+from bs4.element import Tag
+
+
+class SupermarketChain:
+    """
+    A class representing a supermarket chain.
+    """
+    class XMLFilesCategory(Enum):
+        """
+        An enum class of different XML files produced by a supermarket chain
+        """
+        pass
+
+    @property
+    @abstractmethod
+    def promotion_tag_name(self): pass
+
+    @property
+    @abstractmethod
+    def promotion_update_tag_name(self): pass
+
+    @property
+    @abstractmethod
+    def date_format(self): pass
+
+    @property
+    @abstractmethod
+    def date_hour_format(self): pass
+
+    @property
+    @abstractmethod
+    def item_tag_name(self): pass
+
+    @staticmethod
+    def is_valid_store_id(store_id: int) -> bool:
+        """
+        This method returns whether a given store ID is valid (French Natural number).
+
+        :param store_id: A given store ID
+        """
+        return isinstance(store_id, int) and store_id >= 0
+
+    @staticmethod
+    def store_id_type(store_id: str) -> str:
+        """
+        This method used as a type verification for store_id.
+
+        :param store_id: A given store ID
+        :return: The given store_id if valid, else raise an ArgumentTypeError.
+        """
+        if not SupermarketChain.is_valid_store_id(int(store_id)):
+            raise ArgumentTypeError(f"Given store_id: {store_id} is not a valid store_id.")
+        return store_id
+
+    @staticmethod
+    @abstractmethod
+    def get_download_url(store_id: int, category: XMLFilesCategory) -> str:
+        """
+        This method scrapes supermarket's website and returns a url containing the data for a given store and category.
+
+        :param store_id: A given id of a store
+        :param category: A given category
+        :return: A downloadable link of the  data for a given store and category
+        """
+        pass
+
+    @staticmethod
+    @abstractmethod
+    def get_items(promo: Tag, items_dict: Dict[str, str]) -> List[str]:
+        """
+        This method returns a list of the items that participate in a given promo
+
+        :param promo: A given promo
+        :param items_dict: A given dictionary of products
+        """
+        pass