diff --git a/.build b/.build
index b6a7d89..98d9bcb 100644
--- a/.build
+++ b/.build
@@ -1 +1 @@
-16
+17
diff --git a/pylast.py b/pylast.py
index 588401f..051007c 100644
--- a/pylast.py
+++ b/pylast.py
@@ -986,15 +986,15 @@ class _ShelfCacheBackend(object):
     def __init__(self, file_path=None):
         self.shelf = shelve.open(file_path)
 
+    def __iter__(self):
+        return iter(self.shelf.keys())
+
     def get_xml(self, key):
         return self.shelf[key]
 
     def set_xml(self, key, xml_string):
         self.shelf[key] = xml_string
 
-    def has_key(self, key):
-        return key in self.shelf.keys()
-
 
 class _Request(object):
     """Representing an abstract web service operation."""
@@ -1073,7 +1073,7 @@ class _Request(object):
     def _is_cached(self):
         """Returns True if the request is already in cache."""
 
-        return self.cache.has_key(self._get_cache_key())
+        return self._get_cache_key() in self.cache
 
     def _download_response(self):
         """Returns a response body string from the server."""
diff --git a/test_pylast.py b/test_pylast.py
index 18cd691..3a583f5 100755
--- a/test_pylast.py
+++ b/test_pylast.py
@@ -1393,6 +1393,21 @@ class TestPyLast(unittest.TestCase):
         # Assert
         self.helper_only_one_thing_in_top_list(albums, pylast.Album)
 
+    def test_caching(self):
+        # Arrange
+        user = self.network.get_user("RJ")
+
+        # Act
+        self.network.enable_caching()
+        shouts1 = user.get_shouts(limit=1, cacheable=True)
+        shouts2 = user.get_shouts(limit=1, cacheable=True)
+
+        # Assert
+        self.assertTrue(self.network.is_caching_enabled())
+        self.assertEqual(shouts1, shouts2)
+        self.network.disable_caching()
+        self.assertFalse(self.network.is_caching_enabled())
+
 
 if __name__ == '__main__':
     parser = argparse.ArgumentParser(