original_string: public function db($database = null)
      {
          if (empty($database)) {
              $database = $this->database;
          }
          return $this->silex['dbs'][$database];
      }
code: public function db($database = null)
      {
          if (empty($database)) {
              $database = $this->database;
          }
          return $this->silex['dbs'][$database];
      }
code_tokens: public function db ( $ database = null ) { if ( empty ( $ database ) ) { $ database = $ this -> database ; } return $ this -> silex [ 'dbs' ] [ $ database ] ; }
docstring: Gets dbal engine.
  
  @param string $database :  Database to use, check config to see available sources.
  default is the default source.
  
  @return \Doctrine\DBAL\Connection
docstring_tokens: Gets dbal engine .