code: public void setRule(com.google.api.ads.admanager.axis.v201808.FirstPartyAudienceSegmentRule rule) {
          this.rule = rule;
      }
docs: Sets the rule value for this RuleBasedFirstPartyAudienceSegment.
  
  @param rule   * Specifies the rule of the segment which determines user's eligibility
  criteria to be part of
  the segment. This attribute is required.