code: public ListGatewaysResult withGateways(GatewaySummary... gateways) {
          if (this.gateways == null) {
              setGateways(new java.util.ArrayList<GatewaySummary>(gateways.length));
          }
          for (GatewaySummary ele : gateways) {
              this.gateways.add(ele);
          }
          return this;
      }
docs: <p>
  The gateways in the list.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setGateways(java.util.Collection)} or {@link #withGateways(java.util.Collection)} if you want to override
  the existing values.
  </p>
  
  @param gateways
  The gateways in the list.
  @return Returns a reference to this object so that method calls can be chained together.