Fixed type infer on maybe

maybe/src/main/java/com/jmonad/maybe/IMaybe.java

@@ -9,4 +9,4 @@ public interface IMaybe<A> {
   boolean isJust();
   boolean isNothing();
   <B> B maybe(B def, Function<B, A> fn);
-}
+}

maybe/src/main/java/com/jmonad/maybe/Maybe.java

@@ -1,11 +1,11 @@
 package com.jmonad.maybe;
 
-public final class Maybe {
-  public static <T> IMaybe maybe(T value) {
-    if (value instanceof IMaybe) {
-      return (IMaybe) value;
-    }
+public class Maybe {
+  public static <T> IMaybe<T> maybe(IMaybe<T> value) {
+    return value;
+  }
 
-    return value == null ? new Nothing() : new Just<T>(value);
+  public static <T> IMaybe<T> maybe(T value) {
+    return value == null ? new Nothing<T>() : new Just<T>(value);
   }
 }

maybe/src/test/java/com/jmonad/maybe/MaybeTest.java

@@ -9,4 +9,5 @@ public class MaybeTest {
   @Test public void testSample() {
       assert maybe("sample").fromMaybe("").equals("sample");
   }
+
 }