@Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj == null) {
      return false;
    }
    if (getClass() != obj.getClass()) {
      return false;
    }
    Return other = (Return) obj;
    if (doc == null) {
      if (other.doc != null) {
        return false;
      }
    } else if (!doc.equals(other.doc)) {
      return false;
    }
    if (type == null) {
      if (other.type != null) {
        return false;
      }
    } else if (!type.equals(other.type)) {
      return false;
    }
    return true;
  }