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: wrapper_migration_test.go
    path of file: ./repos/lotus/markets/dagstore
    
    the code of the file until where you have to start completion: // stm: #integration
package dagstore

import (
	"context"
	"io"
	"testing"

	mocknet "github.com/libp2p/go-libp2p/p2p/net/mock"
	"github.com/stretchr/testify/require"

	"github.com/filecoin-project/dagstore"
	"github.com/filecoin-project/dagstore/mou
    
func (w *wrappedSA) UnsealSectorAt(ctx context.Context, sectorID abi.SectorNumber, pieceOffset abi.UnpaddedPieceSize, length abi.UnpaddedPieceSize) (mount.Reader, error) {
	r, err := w.UnsealSector(ctx, sectorID, pieceOffset, length)
	if err != nil {
		return nil, err
	}
	return struct {
		io.ReadCloser
		io.Seeker
		io.ReaderAt
	}{
		ReadCloser: r,
		Seeker:     nil,
		ReaderAt:   nil,
	}, err
}