add keypair to transactkey

layercake/layercake/dynamodb.py

@@ -312,12 +312,14 @@ class TransactKey:
     pk: str
     pairs: tuple[KeyPair, ...] = ()
 
-    def __add__(self, other: SortKey) -> 'TransactKey':
+    def __add__(self, other: SortKey | KeyPair) -> 'TransactKey':
         if not isinstance(other, SortKey):
             raise TypeError('Can only add a SortKey to a TransactKey')
 
-        pair = KeyPair(self.pk, other)
-        return TransactKey(pk=self.pk, pairs=self.pairs + (pair,))
+        if isinstance(other, SortKey):
+            other = KeyPair(self.pk, other)
+
+        return TransactKey(pk=self.pk, pairs=self.pairs + (other,))
 
 
 class TransactionCanceledReason(TypedDict):
@@ -756,6 +758,7 @@ class DynamoDBCollection:
     """
     DynamoDBCollection provides a high-level abstraction for performing common
     CRUD operations and queries on a DynamoDB table.
+
     It leverages an underlying persistence layer to handle
     serialization and deserialization of data, key composition, transaction operations,
     and TTL management.
@@ -765,7 +768,7 @@ class DynamoDBCollection:
         - Insert (put) items with optional TTL (time-to-live) settings.
         - Delete items based on keys and conditions.
         - Query items using partition keys or composite key pairs with
-        optional filtering and pagination.
+          optional filtering and pagination.
 
     Parameters
     ----------