[kaathewise]

Yeah, I found `anyhow`'s `Contex` to be a great way of annotating bubbled up errors. The only problem is that using the lazy `with_context` can get somewhat unwieldy. For all the grief people give to Go's `if err != nil` Rust's method chaining can get out of hand too. One particular offender I wrote:

   match operator.propose(py).with_context(|| {
    anyhow!(
   "Operator {} failed while generating a proposal",
   operator.repr(py).unwrap()
  )
   })? {

Which is a combination of `rustfmt` giving up on long lines and also not formatting macros as well as functions