Removed redundant append

server.py

@@ -144,7 +144,6 @@ class LeaderboardServer:
                     first_attributes
                     + list(self.tasks_metadata.keys())
                     + list(dataframe.columns)
-                    + list(extra_attributes_map_word_to_header.keys())
                 ).keys()
                 if key in dataframe.columns
             ]