Function purge_keys 

pub fn purge_keys<T: Config>(
    max_delivery_and_remote_execution_fee: Option<BalanceOf<T>>,
)

Remove session keys for a validator and release the key deposit.

This purges the keys from the Relay Chain.

Unlike set_keys, this does not require the caller to be a registered validator. This is intentional: a validator who has chilled (stopped validating) should still be able to purge their session keys. This matches the behavior of the original pallet-session::purge_keys which allows anyone to call it.

The Relay Chain will reject the call with NoKeys error if the account has no keys set.

Fees: The actual cost of this call is higher than what the weight-based fee estimate shows. In addition to the local transaction weight fee, the caller is charged an XCM fee (delivery + RC execution cost) via XcmExecutor::charge_fees. The relay chain uses UnpaidExecution, so the full remote cost is charged upfront on AssetHub.

When called via a staking proxy, the proxy pays the transaction weight fee, while the delegating account pays the XCM fee.

Max Fee Limit: Users can optionally specify max_delivery_and_remote_execution_fee to limit the delivery + RC execution fee. This does not include the local transaction weight fee. If the fee exceeds this limit, the operation fails with FeesExceededMax. Pass None for unlimited (no cap).

Warning: Doc-Only

This function is an automatically generated, and is doc-only, uncallable stub. See the real version in Pallet::purge_keys.