teamplate.rb

module SEO
  def self.for(record)
    "::SEO::#{record.class_name}".safe_constantize.new(record)
  end
end

class SEO::Base
  attr_reader :record

  def initialize(record)
    @record = record
  end

  def title
    raise NotImplementedError
  end
  
  def descrion
    raise NotImplementedError
  end
end

class SEO::Post
  def title
    post.title
  end
  
  def description
    post.tagline
  end
end

class SEO::User
  #....
end

value_object.rb

module SEO
  def self.for(record)
    "::SEO::#{record.class_name}".safe_constantize.call(record)
  end
end

class SEO::Tags
  attr_reader :title, :descrion

  def initialize(title:, description:)
    @title = title
    @description = description
  end
end

module SEO::Post
  def self.call(post)
    Tags.new(title: post.title, description: post.tagline)
  end  
end

class SEO::User
  #....
end