How Would I Check If A Feature Has No Value

Store Builder Questions
1

I am looking to check if a feature has no value for a specific product. Right now we are using a feature to add text to a box on our product template.

Here is an example of the code: 

                

                                {foreach from=$product.product_features item="feature"}
        	{if $feature.description == 'Shipping Block'}
	        	
{$feature.value}

        	{/if}
            {/foreach}

How would I check if the feature has no value and then display a generic line of text?

2

I tried the following but still no luck.

class="overlay-text">
{foreach from=$product.product_features item="feature"}
{if $feature.description == 'Shipping Block'}
{if $feature.value == ''}

Generic Text

{else}

{$feature.value}

{/if}
{/foreach}