code: func (p Pages) Related(doc related.Document) (Pages, error) {
  	result, err := p.searchDoc(doc)
  	if err != nil {
  		return nil, err
  	}
  
  	if page, ok := doc.(Page); ok {
  		return result.removeFirstIfFound(page), nil
  	}
  
  	return result, nil
  
  }
docs: // Related searches all the configured indices with the search keywords from the
  // supplied document.