You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: migrate.go
    path of file: ./repos/cosmos-sdk/x/slashing/migrations/v4
    
    the code of the file until where you have to start completion: package v4

import (
	"context"

	"github.com/bits-and-blooms/bitset"
	gogotypes "github.com/cosmos/gogoproto/types"

	"cosmossdk.io/errors"
	storetypes "cosmossdk.io/store/types"
	"cosmossdk.io/x/slashing/types"

	"github.com/cosmos/cosmos-sdk/codec"
	sdk "github.com/cosmos/cosmos-sdk/types"
)

// Migrate migrates state to consensus version 4. Specifically, the migration
// deletes all existing validator bitmap entries and replaces them with a real
// "chunked" bitmap.
func Migrate(ctx context.Context, cdc codec.BinaryCodec, store storetypes.KVStore, params types.Params) error {
	// Get all the missed blocks for each validator, based on the existing signing
	// info.
	var missedBlocks []types.ValidatorMissedBlocks
	iterateValidatorSigningInfos(ctx, cdc, store, func(addr sdk.ConsAddress, info types.ValidatorSigningInfo) (stop bool) {
		bechAddr := addr.String()
		localMissedBlocks := GetValidatorMissedBlocks(ctx, cdc, store, addr, params)

		missedBlocks = append(missedBlocks, types.ValidatorMissedBlocks{
			Address:      bechAddr,
			MissedBlocks: localMissedBlocks,
		})

		return false
	})

	// For each missed blocks entry, of which there should only be one per validator,
	// we clear all the old entries and insert the new chunked entry.
	for _, mb := range missedBlo
    
func Migrate(ctx context.Context, cdc codec.BinaryCodec, store storetypes.KVStore, params types.Params) error {
	// Get all the missed blocks for each validator, based on the existing signing
	// info.
	var missedBlocks []types.ValidatorMissedBlocks
	iterateValidatorSigningInfos(ctx, cdc, store, func(addr sdk.ConsAddress, info types.ValidatorSigningInfo) (stop bool) {
		bechAddr := addr.String()
		localMissedBlocks := GetValidatorMissedBlocks(ctx, cdc, store, addr, params)

		missedBlocks = append(missedBlocks, types.ValidatorMissedBlocks{
			Address:      bechAddr,
			MissedBlocks: localMissedBlocks,
		})

		return false
	})

	// For each missed blocks entry, of which there should only be one per validator,
	// we clear all the old entries and insert the new chunked entry.
	for _, mb := range missedBlocks {
		addr, err := sdk.ConsAddressFromBech32(mb.Address)
		if err != nil {
			return err
		}

		deleteValidatorMissedBlockBitArray(ctx, store, addr)

		for _, b := range mb.MissedBlocks {
			// Note: It is not necessary to store entries with missed=false, i.e. where
			// the bit is zero, since when the bitmap is initialized, all non-set bits
			// are already zero.
			if b.Missed {
				if err := setMissedBlockBitmapValue(ctx, store, addr, b.Index, true); err != nil {
					return err
				}
			}
		}
	}

	return nil
}