validated.rb

module MyValidation
  include Dry::Monads::Validated::Mixin

  def Invalid(message)
    super(message.to_s.split('_').map(&:capitalize).join(' '))
  end
end

class CreateUser
  include MyValidation
  include Dry::Monads::List::Mixin

  def call(name, email)
    List::Validated[
      validate_name(name),
      validate_email(email)
    ].traverse.to_result
  end

  def validate_name(name)
    Invalid(:invalid_name)
  end

  def validate_email(email)
    Invalid(:invalid_email)
  end
end


__END__

[1] pry(main)> CreateUser.new.('John', 'john')
=> Failure(List["Invalid Name", "Invalid Email"])