title: Swagger Error Not a valid response definition
body: <p>I have a huge Json file that I'm analyzing with Swagger Editor.</p>
  
  <p>It gives me an error message :</p>
  
  <pre><code>    Swagger Error
  
  Not a valid response definition
  Details
  Object
  code: "ONE_OF_MISSING"
  params: Array [0]
  message: "Not a valid response definition"
  path: Array [5]
  schemaId: "http://swagger.io/v2/schema.json#"
  inner: Array [2]
  level: 900
  type: "Swagger Error"
  description: "Not a valid response definition"
  lineNumber: -1
  </code></pre>
  
  <p>What I want to know is where I should look at.</p>
  
  <p>What I understand : I should look at the "responses" part of my Json. Right ?</p>
  
  <p>Maybe that's only an english issue, but I don't get one_of_missing. What does it mean.</p>
  
  <p>The other errors I had were easy to understand cause it told me which line I had to look at, but what does lineNumber: -1 mean ?</p>
  
  <p>Thanks for your help.</p>