code: public com.google.api.ads.adwords.axis.v201809.cm.VolumeGoalType getVolumeGoalType() {
          return volumeGoalType;
      }
docs: Gets the volumeGoalType value for this PerformanceTarget.
  
  @return volumeGoalType   * The volume goal of the performance target. This property defines
  the way stats data will be
  reported for the time period specified.
  <span class="constraint Selectable">This field can
  be selected using the value "VolumeGoalType".</span><span class="constraint
  Filterable">This field can be filtered on.</span>
  <span class="constraint Required">This field is required
  and should not be {@code null} when it is contained within {@link
  Operator}s : ADD.</span>