```ruby
BraintreeRails::BillingAddressValidator::Validations = BraintreeRails::BillingAddressValidator::Validations.deep_dup
BraintreeRails::BillingAddressValidator::Validations << [:country_code_numeric, :inclusion => {:in => ['124', '840']}]
BraintreeRails::BillingAddressValidator.setup
```

Change the custom validation code to use the easier way
user
```ruby
BraintreeRails::BillingAddressValidator.setup do |validations|
  validations << [:country_name, :inclusion => { :in => ["Canada", "United States of America"], :message => "%{value} is not supported yet." }]
end
```
assistant