anchor.diff:  
   -spec sessions_get_pid(ID :: binary()) -> {ok, Pid :: pid()} | {error, Reason :: atom()}.
   sessions_get_pid(ID) ->
  -    validate_session_pid(lookup(?TTS_SESSIONS, ID)).
  +    validate_pid_value(lookup(?TTS_SESSIONS, ID)).
   
   -spec sessions_update_pid(ID :: binary(), Pid :: pid()) -> ok.
   sessions_update_pid(ID,Pid) ->
  
positive.code: return_ok_or_error(false) ->
      {error, already_used}.
  
  validate_session_pid({ok,Data}) when is_atom(Data) ->
      {error, not_set};
  validate_session_pid(Result) ->
      Result.
  
  
  create_tables() ->
  
negative.code: 
  -define(TTS_SESSIONS,tts_sessions).
  -define(TTS_OIDCP,tts_oidcp).
  -define(TTS_USER,tts_user).
  
  -define(TTS_TABLES,[
                      ?TTS_SESSIONS,
                      ?TTS_OIDCP,
                      ?TTS_USER
                     ]).
  
  init() ->
  