anchor.diff:                      NewTraces = case length(Difference) > 0 of
                           true ->
                               io:format("=> * Adding trace to list to explore.~n", []),
  -                            NewTraces0 ++ [{hd(NewTraceLines), Omissions}];
  +
  +                            case lists:keymember(Difference, 3, NewTraces0) of 
  +                                true ->
  +                                    io:format("=> * Similar trace already exists, ignoring!~n", []),
  +                                    NewTraces0;
  +                                false ->
  +                                    NewTraces0 ++ [{hd(NewTraceLines), Omissions, Difference}]
  +                            end;
                           false ->
                               NewTraces0
                       end,
  
positive.code:                     %% Run the trace.
                      Command = "rm -rf priv/lager; IMPLEMENTATION_MODULE=" ++ os:getenv("IMPLEMENTATION_MODULE") ++ " SHRINKING=true REPLAY=true PRELOAD_OMISSIONS_FILE=" ++ PreloadOmissionFile ++ " REPLAY_TRACE_FILE=" ++ ReplayTraceFile ++ " TRACE_FILE=" ++ TraceFile ++ " ./rebar3 proper --retry | tee /tmp/partisan.output",
                      io:format("Executing command for iteration ~p:~n", [Iteration]),
                      io:format(" ~p~n", [Command]),
                      Output = os:cmd(Command),
  
                      ClassificationsExplored = ClassificationsExplored0 ++ [Classification],
  
negative.code: analyze(_Pass, _PreloadOmissionFile, _ReplayTraceFile, _TraceFile, _Causality, _Annotations, _PreviousIteration, _PreviousClassificationsExplored, []) ->
      ok;
  
  analyze(Pass, PreloadOmissionFile, ReplayTraceFile, TraceFile, Causality, Annotations, PreviousIteration, PreviousClassificationsExplored, [{TraceLines, BaseOmissions, _Difference}|RestTraceLines]) ->
      io:format("Beginning analyze pass: ~p with previous iteration: ~p and previous explored classifications: ~p~n", [Pass, PreviousIteration, PreviousClassificationsExplored]),
  
      %% Filter the trace into message trace lines.
  