title: How to check if attribute is present in value using Mule expression language
body: <p>I want to check logged in user’s authorization based on ‘groupmembership’ header attribute. </p>
  
  <p>The output of </p>
  
  <pre><code>&lt;logger level="INFO" message="groups are =#[message.inboundProperties['GROUPMEMBERSHIP']]" doc:name="Logger"/&gt; is
  [groups are =cn=ZZZ-XXXX-Write-Users,ou= ZZZ-XXXX,ou=1234,ou=Groups,dc=someone,dc=net]
  </code></pre>
  
  <p>Now a user can have multiple group memberships but all I am interested in checking if user is member of ‘ZZZ-XXXX-Write-Users’?</p>
  
  <p>Is there a way in MEL to check that, something like 
  <code>&lt;when expression="#[message.inboundProperties.GROUPMEMBERSHIP.cn != ' ZZZ-XXXX-Write-Users ']"&gt;</code></p>
  
  <p>Is this the right approach or am I missing anything here?</p>