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