Add unlock_hotkeypub method to the wallet. Add unit tests.

bittensor_wallet/wallet.py

@@ -537,6 +537,15 @@ def unlock_coldkey(self) -> Keypair:
         """
         return self.coldkey
 
+    def unlock_coldkeypub(self) -> Keypair:
+        """
+        Unlocks the coldkeypub.
+
+        Returns:
+            coldkeypub (Keypair): the unlocked coldkeypub Keypair.
+        """
+        return self.coldkeypub
+
     def unlock_hotkey(self) -> Keypair:
         """
         Unlocks the hotkey.

tests/test_wallet.py

@@ -522,3 +522,13 @@ def test_unlock_coldkey(mock_wallet):
 
     # Assertions
     assert result == mock_wallet.coldkey
+
+
+def test_unlock_coldkeypub(mock_wallet):
+    """Verify that `unlock_coldkeypub` works correctly."""
+
+    # Call
+    result = mock_wallet.unlock_coldkeypub()
+
+    # Assertions
+    assert result == mock_wallet.coldkeypub