```ruby
module TestWrangler
  module Helper
    BLANK_SELECTION = HashWithIndifferentAccess.new({cohort: nil, experiment: nil, variant: nil})
    
    def test_wrangler_selection
      return @test_wrangler_selection if defined? @test_wrangler_selection
      if cookies['test_wrangler'].present?
        @test_wrangler_selection = HashWithIndifferentAccess.new(JSON.parse(Rack::Utils.unescape(cookies['test_wrangler']))) rescue BLANK_SELECTION
      elsif request.env['test_wrangler'].present?
        @test_wrangler_selection = request.env['test_wrangler'].with_indifferent_access
      else
        @test_wrangler_selection = BLANK_SELECTION
      end
    end

    def complete_experiment
      selection = test_wrangler_selection
      cookies['test_wrangler'] = {value: nil, expires: Time.now}
      selection
    end

  end
end
```

Set cookie expiry to 1 day in the past to ensure deletion
user
```ruby
module TestWrangler
  module Helper
    BLANK_SELECTION = HashWithIndifferentAccess.new({cohort: nil, experiment: nil, variant: nil})
    
    def test_wrangler_selection
      return @test_wrangler_selection if defined? @test_wrangler_selection
      if cookies['test_wrangler'].present?
        @test_wrangler_selection = HashWithIndifferentAccess.new(JSON.parse(Rack::Utils.unescape(cookies['test_wrangler']))) rescue BLANK_SELECTION
      elsif request.env['test_wrangler'].present?
        @test_wrangler_selection = request.env['test_wrangler'].with_indifferent_access
      else
        @test_wrangler_selection = BLANK_SELECTION
      end
    end

    def complete_experiment
      selection = test_wrangler_selection
      cookies['test_wrangler'] = {value: nil, expires: Time.now - 24.hours}
      selection
    end

  end
end
```
assistant