code: func (ssa *SQLStorageAuthority) GetRegistration(ctx context.Context, id int64) (core.Registration, error) {
  	const query = "WHERE id = ?"
  	model, err := selectRegistration(ssa.dbMap.WithContext(ctx), query, id)
  	if err == sql.ErrNoRows {
  		return core.Registration{}, berrors.NotFoundError("registration with ID '%d' not found", id)
  	}
  	if err != nil {
  		return core.Registration{}, err
  	}
  	return modelToRegistration(model)
  }
docs: // GetRegistration obtains a Registration by ID