title: symfony services.yml does not contain valid YAML
body: <p>I get an error in my services.yml : services.yml does not contain valid YAML
  <strong>Symfony 3</strong></p>
  
  <pre><code>redirectionListener:
    class: Gba\GbaBundle\Listener\RedirectionListener
    arguments: [@service_container, @session] 
    tags:
      - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }   
  </code></pre>
  
  <p>Can you help me </p>
  
  <p>Thanks</p>
  
  <p>Screenshot:</p>
  
  <p><img src="https://i.stack.imgur.com/r2wsy.jpg" alt="enter image description here"></p>