code: func CreateSignatureHeader(txh *TransactionHeader) (*common.SignatureHeader, error) {
  
  	signatureHeader := common.SignatureHeader{
  		Creator: txh.creator,
  		Nonce:   txh.nonce,
  	}
  
  	return &signatureHeader, nil
  }
docs: // CreateSignatureHeader creates a SignatureHeader based on the nonce and creator of the transaction header.