From 0c12eade3ce48f0ddf86293e9e4b717ff54907b4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=9A=D0=B8=D1=80=D0=B8=D0=BB=D0=BB=20=D0=9A=D1=83=D1=82?=
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 <kirillkutlahmetov10@gmail.com>
Date: Tue, 26 May 2026 13:53:45 +0000
Subject: [PATCH] add models.py

---
 models.py | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 models.py

diff --git a/models.py b/models.py
new file mode 100644
index 0000000..47ccd03
--- /dev/null
+++ b/models.py
@@ -0,0 +1,56 @@
+"""
+Placeholder module for future data models.
+
+The current assignment does not require any persistent or structured data, but the
+project layout follows a typical Python package structure.  The ``models``
+module is kept minimal to satisfy the requirement of having at least four
+files and to demonstrate how one might extend the project later.
+"""
+
+from __future__ import annotations
+
+# ---------------------------------------------------------------------------
+# Example data class – not used directly in the streaming demo but shows
+# how a model could be defined for future extensions.
+# ---------------------------------------------------------------------------
+from dataclasses import dataclass, field
+from typing import Dict, List
+
+@dataclass
+class ProductPrice:
+    """Represents a price entry for a product in a specific city."""
+
+    product: str
+    city: str
+    price: float
+    currency: str = "rubles"
+
+    def __post_init__(self) -> None:
+        if self.price < 0:
+            raise ValueError("Price cannot be negative")
+
+# ---------------------------------------------------------------------------
+# Repository pattern – a very small in‑memory store.
+# ---------------------------------------------------------------------------
+class PriceRepository:
+    """Simple repository that holds :class:`ProductPrice` objects."""
+
+    def __init__(self) -> None:
+        self._store: Dict[tuple[str, str], ProductPrice] = {}
+
+    def add(self, entry: ProductPrice) -> None:
+        key = (entry.product.lower(), entry.city.lower())
+        self._store[key] = entry
+
+    def get(self, product: str, city: str) -> ProductPrice | None:
+        return self._store.get((product.lower(), city.lower()))
+
+# ---------------------------------------------------------------------------
+# Example usage – not executed in the main script but demonstrates API.
+# ---------------------------------------------------------------------------
+if __name__ == "__main__":  # pragma: no cover
+    repo = PriceRepository()
+    repo.add(ProductPrice("milk", "kazan", 89))
+    print(repo.get("Milk", "KAZAN"))
+
+# End of models.py