code: function(title_id, array) {
  		var used = [title_id];
  
  		// establish which IDs are assigned and if any appear twice, clear out successors.
  		for (var i = 0; i < array.length; i++) {
  			if (TL.Util.trim(array[i].unique_id)) {
  				array[i].unique_id = TL.Util.slugify(array[i].unique_id); // enforce valid
  				if (used.indexOf(array[i].unique_id) == -1) {
  					used.push(array[i].unique_id);
  				} else { // it was already used, wipe it out
  					array[i].unique_id = '';
  				}
  			}
  		};
  
  		if (used.length != (array.length + 1)) {
  			// at least some are yet to be assigned
  			for (var i = 0; i < array.length; i++) {
  				if (!array[i].unique_id) {
  					// use the headline for the unique ID if it's available
  					var slug = (array[i].text) ? TL.Util.slugify(array[i].text.headline) : null;
  					if (!slug) {
  						slug = TL.Util.unique_ID(6); // or generate a random ID
  					}
  					if (used.indexOf(slug) != -1) {
  						slug = slug + '-' + i; // use the index to get a unique ID.
  					}
  					used.push(slug);
  					array[i].unique_id = slug;
  				}
  			}
  		}
  	}
docs: Given an array of slide configs (the events), ensure that each one has a distinct unique_id. The id of the title
  is also passed in because in most ways it functions as an event slide, and the event IDs must also all be unique
  from the title ID.