code: public FaceDetail withLandmarks(Landmark... landmarks) {
          if (this.landmarks == null) {
              setLandmarks(new java.util.ArrayList<Landmark>(landmarks.length));
          }
          for (Landmark ele : landmarks) {
              this.landmarks.add(ele);
          }
          return this;
      }
docs: <p>
  Indicates the location of landmarks on the face. Default attribute.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setLandmarks(java.util.Collection)} or {@link #withLandmarks(java.util.Collection)} if you want to
  override the existing values.
  </p>
  
  @param landmarks
  Indicates the location of landmarks on the face. Default attribute.
  @return Returns a reference to this object so that method calls can be chained together.