code: func (c certificate) Check(d *certdata.Data) *errors.Errors {
  	var e = errors.New(nil)
  
  	for _, cc := range c {
  		if cc.filter != nil && !cc.filter.Check(d) {
  			continue
  		}
  		e.Append(cc.f(d))
  	}
  
  	return e
  }
docs: // Check runs all the registered certificate checks