code: func isEthereumAddress(fl FieldLevel) bool {
  	address := fl.Field().String()
  
  	if !ethAddressRegex.MatchString(address) {
  		return false
  	}
  
  	if ethaddressRegexUpper.MatchString(address) || ethAddressRegexLower.MatchString(address) {
  		return true
  	}
  
  	// checksum validation is blocked by https://github.com/golang/crypto/pull/28
  
  	return true
  }
docs: // IsEthereumAddress is the validation function for validating if the field's value is a valid ethereum address based currently only on the format