def django_boolean_icon(field_val, alt_text=None, title=None):
    """
    Return HTML code for a nice representation of true/false.
    """

    # Origin: contrib/admin/templatetags/admin_list.py
    BOOLEAN_MAPPING = {True: "yes", False: "no", None: "unknown"}
    alt_text = alt_text or BOOLEAN_MAPPING[field_val]
    if title is not None:
        title = 'title="%s" ' % title
    else:
        title = ""
    icon_url = static("feincms/img/icon-%s.gif" % BOOLEAN_MAPPING[field_val])
    return mark_safe(f'<img src="{icon_url}" alt="{alt_text}" {title}/>')

    Return HTML code for a nice representation of true/false.
    
feincms/admin/tree_editor.py