```ruby
module Caching
  class Response
    attr_accessor :response

    def initialize(response)
      self.response = response
      validate!
    end

    def body
      response.body
    end

    def headers
      response.headers
    end

    def ttl
      cache_control[/max-age=([0-9]+)/, 1] || 0 if cache_control == 'no-cache'
    end

    private

    def cache_control
      headers[:cache_control] || ''
    end

    def validate!
      raise ArgumentError, 'response object must implement a `body` method' unless response.respond_to?(:body)
      raise ArgumentError, 'response object must implement a `headers` method' unless response.respond_to?(:headers)
    end
  end
end
```

Refactor and correct ttl for when max-age is defined
user
```ruby
module Caching
  class Response
    attr_accessor :response

    def initialize(response)
      self.response = response
      validate!
    end

    def body
      response.body
    end

    def headers
      response.headers
    end

    def ttl
      max_age.to_i
    end

    private

    def max_age
      cache_control[/max-age=([0-9]+)/, 1] || 0
    end

    def cache_control
      headers[:cache_control] || ''
    end

    def validate!
      raise ArgumentError, 'response object must implement a `body` method' unless response.respond_to?(:body)
      raise ArgumentError, 'response object must implement a `headers` method' unless response.respond_to?(:headers)
    end
  end
end
```
assistant