def METHOD_NAME(model, form, field_name):
    """
    Read tags form field into model field
    :param model: Model containing tag field
    :param form: Form data from front-end
    :param field_name: Name of field shared by model and form
    :return: True if changes to model tag field were made
    """
    form_tags = read_form_field(form, field_name)
    if form_tags is not None:
        if is_json_string(form_tags):
            # Convert full tag data to comma-delimited slugs string
            form_tags_json = json.loads(form_tags)
            form_tag_slugs = list(map(lambda tag: tag['tag_name'], form_tags_json))
            form_tags = ','.join(form_tag_slugs)
        return Tag.merge_tags_field(getattr(model, field_name), form_tags)
    return False