additional function for exposure trait

Signed-off-by: Uncle Stretch <uncle.stretch@ghostchain.io>

pallets/traits/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ghost-traits"
-version = "0.3.31"
+version = "0.3.32"
 license.workspace = true
 authors.workspace = true
 edition.workspace = true
@@ -10,10 +10,12 @@ repository.workspace = true
 [dependencies]
 frame-support = { workspace = true }
 sp-runtime = { workspace = true }
+sp-std = { workspace = true }
 
 [features]
 default = ["std"]
 std = [
     "frame-support/std",
     "sp-runtime/std",
+    "sp-std/std",
 ]

pallets/traits/src/exposure.rs

@@ -1,6 +1,9 @@
 use sp_runtime::traits::AtLeast32BitUnsigned;
 
 pub trait ExposureListener<Balance: AtLeast32BitUnsigned, AccountId> {
+    fn get_accounts_by_indexes(
+        indexes: impl Iterator<Item = usize>,
+    ) -> sp_std::prelude::Vec<AccountId>;
     fn get_account_by_index(index: usize) -> Option<AccountId>;
     fn get_total_exposure() -> Balance;
     fn get_validator_exposure(index: &AccountId) -> Balance;