code: public UpdateDomainAssociationRequest withSubDomainSettings(SubDomainSetting... subDomainSettings) {
          if (this.subDomainSettings == null) {
              setSubDomainSettings(new java.util.ArrayList<SubDomainSetting>(subDomainSettings.length));
          }
          for (SubDomainSetting ele : subDomainSettings) {
              this.subDomainSettings.add(ele);
          }
          return this;
      }
docs: <p>
  Setting structure for the Subdomain.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setSubDomainSettings(java.util.Collection)} or {@link #withSubDomainSettings(java.util.Collection)} if
  you want to override the existing values.
  </p>
  
  @param subDomainSettings
  Setting structure for the Subdomain.
  @return Returns a reference to this object so that method calls can be chained together.