Sylius\Behat\Page\Admin\Customer\CreatePageInterface::specifyFirstName PHP Method

    public function specifyFirstName($name);

 /**
  * @When /^I specify (?:their|his) first name as "([^"]*)"$/
  */
 public function iSpecifyItsFirstNameAs($name)
 {
     $this->createPage->specifyFirstName($name);
 }