def METHOD_NAME(sender, **kwargs):
    '''This will set the 'created' field on any object to the current UTC time
    if it is unset.
    Additionally, this will set the 'last_modified' field on any object to the
    current UTC time on any save of the object.
    For use as a pre_save signal handler.'''
    obj = kwargs['instance']
    time = now()
    if hasattr(obj, 'created') and not obj.created:
        obj.created = time
    if hasattr(obj, 'last_modified'):
        obj.last_modified = time