code: public void setColumns(com.google.api.ads.admanager.axis.v201808.Column[] columns) {
          this.columns = columns;
      }
docs: Sets the columns value for this ReportQuery.
  
  @param columns   * The list of trafficking statistics and revenue information
  being requested
  in the report. The generated report will contain the
  columns in the same
  order as requested. This field is required.