code: func (f URIFormatChecker) IsFormat(input interface{}) bool {
  	asString, ok := input.(string)
  	if !ok {
  		return false
  	}
  
  	u, err := url.Parse(asString)
  
  	if err != nil || u.Scheme == "" {
  		return false
  	}
  
  	return !strings.Contains(asString, `\`)
  }
docs: // IsFormat checks if input is correctly formatted  URI with a valid Scheme per RFC3986