a trait to cast User into Vec

UserRustTraits.rs

impl From<&User> for Vec<f64> {
    fn from(user: &User) -> Vec<f64> {
        vec![
            user.senior_citizen as f64,
            user.tenure as f64,
            user.monthly_charges,
            user.total_charges,
            // ... more fields are omitted for brevity
            ]
    }
}

done