function `fetch_proof` is never used

function `fetch_challenges` is never used

the use of negated comparison operators on partially ordered types produces code that is hard to read and refactor, please consider using the `partial_cmp` method instead, to make it clear that the two values could be incomparable

using `clone` on type `<T as Config>::StorageDataUnit` which implements the `Copy` trait

unnecessary map of the identity function

using `clone` on type `<T as Config>::ValuePropId` which implements the `Copy` trait

using `clone` on type `<T as Config>::ValuePropId` which implements the `Copy` trait

using `clone` on type `<T as Config>::ValuePropId` which implements the `Copy` trait

using `clone` on type `<T as Config>::ValuePropId` which implements the `Copy` trait