title: Find whether an object with multifields contains a string
body: <pre><code>{
      "_id" : ObjectId("5811b03d231d884982672ddd"),
      "person-name" : "Bell, Lee Phillip",
      "info" : {
          "trivia" : [
              "Mother-in-law of 'Colleen Bell (II)' (qv) and 'Maria Arena Bell' (qv).",
              "Mother of actress 'Lauralee Bell' (qv), writer/producer 'Bradley Bell (I)' (qv) and TV executive 'William J. Bell Jr.' (qv)."
          ],
          "birthnotes" : [
              "Chicago, Illinois, USA"
          ],
          "spouse" : [
              "'William J. Bell' (qv) (October 1954 - 29 April 2005) (his death); 3 children"
          ],
          "birthname" : [
              "Phillip, Lee"
          ]
      }
  }
  </code></pre>
  
  <p>I want to find in the field "info" which contains "Opera". Does anyone have an idea?</p>