code: func (ssa *SQLStorageAuthority) UpdateRegistration(ctx context.Context, reg core.Registration) error {
  	const query = "WHERE id = ?"
  	model, err := selectRegistration(ssa.dbMap.WithContext(ctx), query, reg.ID)
  	if err == sql.ErrNoRows {
  		return berrors.NotFoundError("registration with ID '%d' not found", reg.ID)
  	}
  
  	updatedRegModel, err := registrationToModel(&reg)
  	if err != nil {
  		return err
  	}
  
  	// Copy the existing registration model's LockCol to the new updated
  	// registration model's LockCol
  	updatedRegModel.LockCol = model.LockCol
  	n, err := ssa.dbMap.WithContext(ctx).Update(updatedRegModel)
  	if err != nil {
  		return err
  	}
  	if n == 0 {
  		return berrors.NotFoundError("registration with ID '%d' not found", reg.ID)
  	}
  
  	return nil
  }
docs: // UpdateRegistration stores an updated Registration