def _entities_to_choices(entities, answer):
    """Generate a multichoice question template."""
    if len(entities) > 26:
        raise ValueError('Too many choices: {}'.format(len(entities)))
    entity_dict = {}
    choices_template = ''
    answer_choice = None
    for i, entity in enumerate(entities):
        choices_template += '  '
        entity_name = 'entity_{}'.format(i)
        entity_dict[entity_name] = entity
        letter = chr(ord('a') + i)
        choices_template += '({letter}) {{{entity_name}}}'.format(letter=
            letter, entity_name=entity_name)
        if entity is answer:
            assert answer_choice is None
            answer_choice = letter
    assert answer_choice is not None
    return entity_dict, choices_template, answer_choice
