mongodb/learnmongodbthehardway

Hello :) I am working on a fairly straight forward task (I think).

This code is just me fleshing out the new feature (utilizing the aggregrate method):

    async fn top_phrases(&self) -> Result<()> {
        let collection = self.handle.collection::<Document>("logged_messages");
        let pipeline = vec![
            doc! { 
                "$group": { 
                    "_id": "$trigger",
                    "phrase": { "$first": "$phrase" },
                    "count": { "$sum": 1 },
                },
            },
            doc! { "$count": "-1" },
            doc! { "$limit": 10 },
        ];
        let mut phrases = collection.aggregate(pipeline, None).await?;
        while let Some(phrase) = phrases.next().await {
            let test: PhraseFrequency = from_document(phrase?)?;
            println!("{}", test.to_message());
        }
        Ok(())
    }

Here is my struct that derives the Deserialize trait:

#[derive(Deserialize)]
pub struct PhraseFrequency {
    phrase: String,
    count: usize,
}

When trying to run I panic on this line:

            Message::TopPhrases => {
                let _ = self.top_phrases().await.unwrap();
            }

The panic message states: missing fieldphrase``