```ruby
module MailForm
	class Base
		include ActiveModel::AttributeMethods
		attribute_method_prefix 'clear_'

		def self.attributes(*names)
			attr_accessor(*names)
			define_attribute_methods(names)
		end

		protected

		def clear_attribute(attribute)
			send("#{attribute}=", nil)
		end
	end
end
```

Define '?' as a suffix
user
```ruby
module MailForm
	class Base
		include ActiveModel::AttributeMethods
		attribute_method_prefix 'clear_'
		attribute_method_suffix '?'

		def self.attributes(*names)
			attr_accessor(*names)
			define_attribute_methods(names)
		end

		protected

		def clear_attribute(attribute)
			send("#{attribute}=", nil)
		end

		def attribute?(attribute)
			send(attribute).present?
		end
	end
end
```
assistant