code: @SuppressWarnings("unused")
          public Map<A, B> toMap() {
              Map<A, B> m = new HashMap<A, B>();
              m.put(_1, _2);
              return m;
          }
docs: Convert this {@code Tuple} instance into a Map with one key,value pair. Where
  {@code key} is {@code _1} and {@code value} is {@code _2};
  
  @return the Map as described