code: public CampaignResponse withAdditionalTreatments(TreatmentResource... additionalTreatments) {
          if (this.additionalTreatments == null) {
              setAdditionalTreatments(new java.util.ArrayList<TreatmentResource>(additionalTreatments.length));
          }
          for (TreatmentResource ele : additionalTreatments) {
              this.additionalTreatments.add(ele);
          }
          return this;
      }
docs: Treatments that are defined in addition to the default treatment.
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setAdditionalTreatments(java.util.Collection)} or {@link #withAdditionalTreatments(java.util.Collection)}
  if you want to override the existing values.
  </p>
  
  @param additionalTreatments
  Treatments that are defined in addition to the default treatment.
  @return Returns a reference to this object so that method calls can be chained together.