original_string: public function listen(Closure $callback)
      {
          if (isset($this->events)) {
              $this->events->listen(Events\QueryExecuted::class, $callback);
          }
      }
code: public function listen(Closure $callback)
      {
          if (isset($this->events)) {
              $this->events->listen(Events\QueryExecuted::class, $callback);
          }
      }
code_tokens: public function listen ( Closure $ callback ) { if ( isset ( $ this -> events ) ) { $ this -> events -> listen ( Events \ QueryExecuted :: class , $ callback ) ; } }
docstring: Register a database query listener with the connection.
  
  @param  \Closure  $callback
  @return void
docstring_tokens: Register a database query listener with the connection .