radio_choice.pt

<span tal:repeat="choice field.widget.values" tal:omit-tag="">
  <label for="${field.oid}-${repeat.choice.index}">${choice[1]}</label>
  <input tal:attributes="checked choice[0] == cstruct; class field.widget.css_class;"
         type="radio"
         name="${field.name}"
         value="${choice[0]}"
         id="${field.oid}-${repeat.choice.index}"/>
</span>