public static void deassignTruthValue(Proposition self, Keyword updatemode) {
    { Proposition object000 = self;
      TruthValue value000 = null;
      Stella_Object oldValue000 = object000.truthValue;
      Stella_Object newValue000 = Stella_Object.updateInContext(oldValue000, value000, object000.homeContext, false);

      if (!((oldValue000 != null) &&
          (oldValue000.primaryType() == Logic.SGT_STELLA_CS_VALUE))) {
        object000.truthValue = newValue000;
      }
    }
    if (!(updatemode == Logic.KWD_RETRACT_INCONSISTENT)) {
      Logic.handleOutOfDateInferenceCache(Logic.KWD_RETRACT, self);
      Proposition.updateLinksAndTimestamps(self, updatemode);
    }
  }