code: func (s *Store) RetrieveHash(name string, version string) ([]byte, error) {
  	installedChaincodes, err := s.ListInstalledChaincodes()
  	if err != nil {
  		return nil, errors.WithMessage(err, "error getting installed chaincodes")
  	}
  
  	for _, installedChaincode := range installedChaincodes {
  		if installedChaincode.Name == name && installedChaincode.Version == version {
  			return installedChaincode.Id, nil
  		}
  	}
  
  	err = &CodePackageNotFoundErr{
  		Name:    name,
  		Version: version,
  	}
  
  	return nil, err
  }
docs: // RetrieveHash retrieves the hash of a chaincode install package given the
  // name and version of the chaincode