marhep
diff --git a/‎openai/api_resources/higherlevel.py
+6-3 b/‎openai/api_resources/higherlevel.py
+6-3
@@ -5,10 +5,13 @@ class HigherLevel(EngineAPIResource):
     api_prefix = "higherlevel"
 
     def get_url(self, base):
-        return "/%s/%ss" % (self.api_prefix, base)
+        return "/%s/%s" % (self.api_prefix, base)
 
     def classification(self, **params):
-        return self.request("post", self.get_url("classification"), params)
+        return self.request("post", self.get_url("classifications"), params)
 
     def answer(self, **params):
-        return self.request("post", self.get_url("answer"), params)
+        return self.request("post", self.get_url("answers"), params)
+
+    def retriever_file_set_search(self, **params):
+        return self.request("post", self.get_url("retriever_file_set_search"), params)