code: public function insert($data)
      {
          if (false !== $data = $this->_do_pre_create($data)) {
              $this->_database->insert($this->_table, $data);
              $insert_id = $this->_database->insert_id();
  
              $this->trigger('after_create', $insert_id);
  
              return $insert_id;
          }
  
          return false;
      }
docs: Insert a new row into the table. $data should be an associative array
  of data to be inserted. Returns newly created ID.
  @param $data
  @return bool