code: public com.google.api.ads.adwords.axis.v201809.cm.AdvertisingChannelSubType getAdvertisingChannelSubType() {
          return advertisingChannelSubType;
      }
docs: Gets the advertisingChannelSubType value for this Campaign.
  
  @return advertisingChannelSubType   * Optional refinement of advertisingChannelType. Must be a valid
  sub-type of the parent channel
  type. May only be set for new campaigns and cannot
  be changed once set.
  <span class="constraint ReadOnly">This field is read
  only and will be ignored when sent to the API for the following {@link
  Operator}s: SET.</span>