Index: uspace/lib/cpp/include/impl/unordered_map.hpp
===================================================================
--- uspace/lib/cpp/include/impl/unordered_map.hpp	(revision 6562af2d2acdb7c150ebc5e9c883a7f3586db32a)
+++ uspace/lib/cpp/include/impl/unordered_map.hpp	(revision 49343fe1aa5aa5bc541b46f5f476961d249ba819)
@@ -595,10 +595,16 @@
             mapped_type& at(const key_type& key)
             {
-                // TODO: implement
+                auto it = find(key);
+
+                // TODO: throw out_of_range if it == end()
+                return it->second;
             }
 
             const mapped_type& at(const key_type& key) const
             {
-                // TODO: implement
+                auto it = find(key);
+
+                // TODO: throw out_of_range if it == end()
+                return it->second;
             }