code: func (s *MigrationService) SetLFSPreference(ctx context.Context, owner, repo string, in *Import) (*Import, *Response, error) {
  	u := fmt.Sprintf("repos/%v/%v/import/lfs", owner, repo)
  	req, err := s.client.NewRequest("PATCH", u, in)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	// TODO: remove custom Accept header when this API fully launches
  	req.Header.Set("Accept", mediaTypeImportPreview)
  
  	out := new(Import)
  	resp, err := s.client.Do(ctx, req, out)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return out, resp, nil
  }
docs: // SetLFSPreference sets whether imported repositories should use Git LFS for
  // files larger than 100MB. Only the UseLFS field on the provided Import is
  // used.
  //
  // GitHub API docs: https://developer.github.com/v3/migration/source_imports/#set-git-lfs-preference