Use Tuple as response

client/data/src/main/java/helper/Tuple.java

@@ -0,0 +1,27 @@
+package helper;
+
+public class Tuple<X, Y> {
+    public final X key;
+    public final Y value;
+
+    public Tuple(X key, Y value) {
+        this.key = key;
+        this.value = value;
+    }
+
+    public X getKey() {
+        return key;
+    }
+
+    public Y getValue() {
+        return value;
+    }
+
+    @Override
+    public String toString() {
+        return "Tuple{" +
+                "key=" + key +
+                ", value=" + value +
+                '}';
+    }
+}