1 files changed, 16 insertions, 2 deletions
diff --git a/poker/models.py b/poker/models.py
index e62df17..5ecda90 100644
--- a/poker/models.py
+++ b/poker/models.py
@@ -1,4 +1,4 @@
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, validator
 
 from poker.constants import Suit, Value
 
@@ -9,8 +9,22 @@ class Card(BaseModel):
     suit: Suit
     value: Value
 
+    def __hash__(self) -> int:
+        """Hash function."""
+        return hash(f"{self.value} {self.suit}")
+
+
+HandType = tuple[Card, Card, Card, Card, Card]
+
 
 class Hand(BaseModel):
     """Hand domain model class."""
 
-    cards: list[Card] = Field(..., min_length=5, max_length=5)
+    cards: HandType
+
+    @validator("cards")
+    def validate_unique(cls, cards: HandType) -> HandType:
+        """Validate hand comprises unique cards."""
+        if len(cards) != len(set(cards)):
+            raise ValueError("Hand contains duplicate cards.")
+        return cards