code: function probeOutputTransform(/*headers, data*/) {
    /*jshint validthis:true */
    var operation = this;
  
    var statusCode = operation.responseStatusCode;
    var exists     = (statusCode === 200) ? true : false;
    if (operation.contentOnly === true) {
      return exists;
    }
  
    var output = exists ? operation.responseHeaders : {};
    output.uri    = operation.uri;
    output.exists = exists;
  
    return output;
  }
docs: Provides functions to write, read, query, or perform other operations
  on documents in the database. For operations that modify the database,
  the client must have been created for a user with the rest-writer role.
  For operations that read or query the database, the user need only have
  the rest-reader role.
  @namespace documents
   @ignore