# EIP-6914 -- Fork Choice

## Table of contents

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- [Introduction](#introduction)
- [Fork choice](#fork-choice)
  - [Handlers](#handlers)
    - [`on_reused_index`](#on_reused_index)

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## Introduction

This is the modification of the fork choice according to EIP-6914.

## Fork choice

A new handler is added with this upgrade:

- `on_reused_index(store, index)` whenever a validator index `index: ValidatorIndex` is reused. That is, [`get_index_for_new_validator()`](./beacon-chain.md#get_index_for_new_validator) provides an index due to a return value of `True` from [`is_reusable_validator()`](./beacon-chain.md#is_reusable_validator).

This new handler is used to update the list of equivocating indices to be synchronized with the canonical chain.

### Handlers

#### `on_reused_index`

```python
def on_reused_index(store: Store, index: ValidatorIndex) -> None:
    store.equivocating_indices.discard(index)
```