code: public java.util.List<String> getInstanceGroupTypes() {
          if (instanceGroupTypes == null) {
              instanceGroupTypes = new com.amazonaws.internal.SdkInternalList<String>();
          }
          return instanceGroupTypes;
      }
docs: <p>
  The type of instance group for which to list the instances.
  </p>
  
  @return The type of instance group for which to list the instances.
  @see InstanceGroupType