code: public int locate(Attribute attr) {
          List lst;
          int i;
          int max;
  
          if (attr.symbol < attrs.size()) {
              lst = (List) attrs.get(attr.symbol);
              max = lst.size();
              for (i = 0; i < max; i++) {
                  if (attr == lst.get(i)) {
                      return i;
                  }
              }
          }
          return -1;
      }
docs: returns location or -1