code: public ListSubscriptionsByTopicResult withSubscriptions(Subscription... subscriptions) {
          if (this.subscriptions == null) {
              setSubscriptions(new com.amazonaws.internal.SdkInternalList<Subscription>(subscriptions.length));
          }
          for (Subscription ele : subscriptions) {
              this.subscriptions.add(ele);
          }
          return this;
      }
docs: <p>
  A list of subscriptions.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setSubscriptions(java.util.Collection)} or {@link #withSubscriptions(java.util.Collection)} if you want
  to override the existing values.
  </p>
  
  @param subscriptions
  A list of subscriptions.
  @return Returns a reference to this object so that method calls can be chained together.