You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: group_remove_member.rs
    path of file: ./repos/backend/crates/delta/src/routes/channels
    
    the code of the file until where you have to start completion: use revolt_quark::{
    models::{Channel, User},
    Db, EmptyResponse, Error, Permission, Ref, Result,
};

/// # Remove Member from Group
///
/// Removes a user from the group.
#[openapi(tag = "Groups")]
#[delete("/<target>/recipients/<member>")]
pub async fn req(db: &Db, user: User, target: Ref, member: Ref) -> Result<EmptyResponse> {
    if user.bot.is_some() {
        return Err(Error::IsBot);
    }

    let channel = target.as_channel(db).await?;

    match &channel {
        Channel::Group {
            owner, recipients, ..
        } => {
            if &user.id != owner {
                return Error::from_permission(Permission::ManageChannel);
            }

       
    
    async fn fail_not_in_group() {
        let harness = TestHarness::new().await;
        let (_, session, user) = harness.new_user().await;
        let (_, _, other_user) = harness.new_user().await;

        let group = Channel::create_group(
            &harness.db,
            v0::DataCreateGroup {
                name: TestHarness::rand_string(),
                ..Default::default()
            },
            user.id.to_string(),
        )
        .await
        .unwrap();

        let response = harness
            .client
            .delete(format!(
                "/channels/{}/recipients/{}",
                group.id(),
                other_user.id
            ))
            .header(Header::new("x-session-token", session.token.to_string()))
            .dispatch()
            .await;

        dbg!(response.into_string().await);
        // FIXME: finish impl
        // assert_eq!(response.status(), Status::NotFound);
    }