code: func (b *Block) resolveReceipts(ctx context.Context) ([]*types.Receipt, error) {
  	if b.receipts == nil {
  		hash := b.hash
  		if hash == (common.Hash{}) {
  			header, err := b.resolveHeader(ctx)
  			if err != nil {
  				return nil, err
  			}
  			hash = header.Hash()
  		}
  
  		receipts, err := b.backend.GetReceipts(ctx, hash)
  		if err != nil {
  			return nil, err
  		}
  		b.receipts = []*types.Receipt(receipts)
  	}
  	return b.receipts, nil
  }
docs: // resolveReceipts returns the list of receipts for this block, fetching them
  // if necessary.