[KHM] Implemented Eradicator Valkyrie (#7367)

Mage/src/main/java/mage/abilities/keyword/HexproofFromPlaneswalkersAbility.java

@@ -0,0 +1,47 @@
+package mage.abilities.keyword;
+
+import mage.MageObject;
+import mage.game.Game;
+
+import java.io.ObjectStreamException;
+
+/**
+ * Hexproof from planesalkers
+ *
+ * @author weirddan455
+ */
+public class HexproofFromPlaneswalkersAbility extends HexproofBaseAbility {
+
+    private static final HexproofFromPlaneswalkersAbility instance;
+
+    static {
+        instance = new HexproofFromPlaneswalkersAbility();
+    }
+
+    private Object readResolve() throws ObjectStreamException {
+        return instance;
+    }
+
+    public static HexproofFromPlaneswalkersAbility getInstance() {
+        return instance;
+    }
+
+    private HexproofFromPlaneswalkersAbility() {
+        super();
+    }
+
+    @Override
+    public boolean checkObject(MageObject source, Game game) {
+        return source.isPlaneswalker();
+    }
+
+    @Override
+    public HexproofFromPlaneswalkersAbility copy() {
+        return instance;
+    }
+
+    @Override
+    public String getRule() {
+        return "hexproof from planeswalkers";
+    }
+}