anchor.diff:        </div>
   
         <div class="FormField__input FormField__input--multiple">
  -        <input type="text" name="lesson[key_concepts][]" class="Input Input--multiple" data-values='<%= @lesson_obj.key_concepts.to_json %>' value="" placeholder="+ Add a new concept" id="lesson_key_concepts_1" />
  +        <input type="text" name="lesson[key_concepts][]" class="Input Input--multiple" data-values='<%= @lesson_obj.key_concepts.to_json %>' value="" placeholder="+ Add a new concept" id="lesson_key_concepts_1" required />
         </div>
   
       </div>
  
positive.code:       </div>
  
        <div class="FormField__input FormField__input--multiple">
          <input type="text" name="lesson[key_vocabularies][]" class="Input Input--multiple" data-values='<%= @lesson_obj.key_vocabularies.to_json %>' value="" placeholder="+ Add a new vocabulary" id="lesson_key_vocabularies_1" />
        </div>
  
      </div>
  
negative.code:       </div>
  
        <div class="FormField__input FormField__input--multiple">
          <input type="text" name="lesson[key_formulas][]" class="Input Input--multiple" data-values='<%= @lesson_obj.key_formulas.to_json %>' value="" placeholder="+ Add a new formula" id="lesson_key_formulas_1" required />
        </div>
  
      </div>
  