Sylius\Behat\Page\Admin\Customer\ShowPageInterface::getSuccessFlashMessage PHP Method

    public function getSuccessFlashMessage();

 /**
  * @Then I should see that impersonating :email was successful
  */
 public function iShouldSeeThatImpersonatingWasSuccessful($email)
 {
     Assert::contains($this->customerShowPage->getSuccessFlashMessage(), $email);
 }