code: public com.google.api.ads.adwords.axis.v201809.cm.Function getMatchingFunction() {
          return matchingFunction;
      }
docs: Gets the matchingFunction value for this CampaignFeed.
  
  @return matchingFunction   * Matching function associated with the CampaignFeed.
  The matching function will return true/false indicating
  which feed items may serve.
  <span class="constraint Selectable">This field can
  be selected using the value "MatchingFunction".</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>