code: func isDataURI(fl FieldLevel) bool {
  
  	uri := strings.SplitN(fl.Field().String(), ",", 2)
  
  	if len(uri) != 2 {
  		return false
  	}
  
  	if !dataURIRegex.MatchString(uri[0]) {
  		return false
  	}
  
  	return base64Regex.MatchString(uri[1])
  }
docs: // IsDataURI is the validation function for validating if the field's value is a valid data URI.