code: @Override
    public void putSingle(String key, SoyData value) {
      map.put(key, value);
    }
docs: Important: Do not use outside of Soy code (treat as superpackage-private).
  
  <p>Puts data into this data object at the specified key.
  
  @param key An individual key.
  @param value The data to put at the specified key.