code: func (f URIReferenceFormatChecker) IsFormat(input interface{}) bool {
  	asString, ok := input.(string)
  	if !ok {
  		return false
  	}
  
  	_, err := url.Parse(asString)
  	return err == nil && !strings.Contains(asString, `\`)
  }
docs: // IsFormat checks if input is a correctly formatted URI or relative-reference per RFC3986