code: public void add(Make make)
    {
      if (make == this)
        throw new IllegalArgumentException("Can't add self as a dependency.");
  
      int p = _makeList.indexOf(make);
  
      // matching make overrides old ones
      // server/10ik
      if (p >= 0) {
        Make oldMake = _makeList.get(p);
  
        if (oldMake != make)
          _makeList.add(p, make);
      }
      else
        _makeList.add(make);
    }
docs: Adds a dependency.