code: public function selectColumns($columns)
      {
          if (!is_array($columns)) {
              $columns = func_get_args();
          }
          $this->request->setParam(
              'selectColumns',
              $this->request->getModule() . '(' . implode(',', $columns) . ')'
          );
          return $this;
      }
docs: Column names to select i.e, ['Last Name', 'Website', 'Email']
  When not set defaults to all columns
  
  @param array|string $columns
  @return GetSearchRecordsByPDC