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: remove.go
    path of file: ./repos/sealer/vendor/github.com/ipfs/go-ipfs/blocks/blockstoreutil
    
    the code of the file until where you have to start completion: // Package blockstoreutil provides utility functions for Blockstores.
package blockstoreutil

import (
	"context"
	"fmt"
	"io"

	cid "github.com/ipfs/go-cid"
	bs "github.com/ipfs/go-ipfs-blockstore"
	pin "github.com/ipfs/go-ipfs-pinner"
)

// RemovedBlock is used to represent the result of removing 
    
func FilterPinned(ctx context.Context, pins pin.Pinner, out chan<- interface{}, cids []cid.Cid) []cid.Cid {
	stillOkay := make([]cid.Cid, 0, len(cids))
	res, err := pins.CheckIfPinned(ctx, cids...)
	if err != nil {
		out <- &RemovedBlock{Error: fmt.Sprintf("pin check failed: %s", err)}
		return nil
	}
	for _, r := range res {
		if !r.Pinned() {
			stillOkay = append(stillOkay, r.Key)
		} else {
			out <- &RemovedBlock{
				Hash:  r.Key.String(),
				Error: r.String(),
			}
		}
	}
	return stillOkay
}