Save screenshot of a failed Behat step

SomethingContext.php

<?php

/**
 * @AfterStep
 */
public function takeScreenshotAfterFailedStep($event)
{
  if ($event->getTestResult()->getResultCode() === \Behat\Testwork\Tester\Result\TestResult::FAILED) {
    $driver = $this->getSession()->getDriver();
    if ($driver instanceof \Behat\Mink\Driver\Selenium2Driver) {
		   $stepText = $event->getStep()->getText();
		   $fileName = preg_replace('#[^a-zA-Z0-9\._-]#', '', $stepText).'.png';
		   $filePath = sys_get_temp_dir();
		   $this->saveScreenshot($fileName, $filePath);
		   print "Screenshot for '{$stepText}' placed in ".$filePath.DIRECTORY_SEPARATOR.$fileName."\n";
	  }
  }
}