title: Aggregation With Golang/Mongodb Gives Error "Missing type in composite literal"
body: <p>I am trying to get users in a certain age range via aggregation.</p>
  
  <p><strong>Edit:</strong> I am able to work through mongo shell, query works fine however I am not able to make it work with go</p>
  
  <blockquote>
    <p>This code gives me "missing type in composite literal" error.</p>
  </blockquote>
  
  <p>What am I missing here?</p>
  
  <pre><code>lte := 10
  gte := 0
  
  operations := []bson.M{
      {
          "$match":{
              "$and":[]interface{}{
                  bson.M{"age":{"$gte":gte}},
                  bson.M{"age":{"$lte":lte}},
              },
          },
      },
      {
          "$group":bson.M{"_id":"$user_id"},
      },
  
  }
  
  r := []bson.M{}
  
  pipe := c.Pipe(operations)
  err := pipe.All(&amp;r)
  if err != nil {
      logrus.Errorf("Error:  %v", err)
      return err
  }
  </code></pre>