code: public List<V> put(String name, V value) {
          if (value == null) {
              return super.put(name, null);
          }
          List<V> vals = new ArrayList<>();
          vals.add(value);
          return put(name, vals);
      }
docs: Put multi valued entry.
  
  @param name  The entry key.
  @param value The simple value
  @return The previous value or null.