model_helpers.py

def model_attrs_unicode(instance, attrs=None):
    """Helper for creating simple instance string descriptions.
    Accepts a list of string attributes names or functions that can be given by
    specifying attrs or defining __UNICODE__ATTRS on the model.

    If a get_{fieldname}_display method exists, it will be used instead of
    simple getattr.

    Attrs can contain function that accept model instance and return
    (attrname, val) pairs, both must be unicode strings.

    Keyword arguments:
    instance -- source for fields
    attrs -- attributes to generate unicode representation from

    """

    if attrs is None:
        display_attrs = getattr(instance, '__UNICODE__ATTRS', None)
    else:
        display_attrs = attrs

    if display_attrs is None:
        return None

    def get_field_display(attrname):
        display = getattr(instance, 'get_{}_display'.format(attrname), None)
        if display is not None:
            val = display
            if callable(display):
                val = display()
        else:
            if callable(attrname):
                attrname, val = attrname(instance)
            else:
                val = getattr(instance, attrname)

        return u'{}: {}'.format(attrname, val)

    vals = [get_field_display(attrname) for attrname in display_attrs]
    return u', '.join(vals)