It is necessary to add to the html form so that from the SELECT or OPTION tag the infa is transferred to a specific field form.CharFiled . It is necessary in order to make the logic in the SELECT . As some OPTION may not be available depending on the value in Product(models.Model)
So if item_1 = False, item_2 = True , then the following is in html:
<select> {% if item_1 %} <option>Item1</option> {% endif %} {% if item_2 %} <option>Item2</option> {% endif %} </select> The user will only select item_2 and need this value to be written in the usual form.CharField field. That is, assign either SELECT or OPTION to {{ form.items_example }}