error: redundant closure
   --> src/algorithms/hmac.rs:209:22
    |
209 |             .map_err(|err| signature::Error::from_source(err))?;
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `signature::Error::from_source`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_closure
    = note: `-D clippy::redundant-closure` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::redundant_closure)]`