def is_unique(model, field_element):
    """
    Checks uniqueness of given field_element value after it will
    be saved in the database
    
    This straightforward check lets to avoid duplicates in the database
    without need to set unique constraints there
    """
    params = {field_element.attrib['name']: field_element.text}
    return not model.objects.filter(**params).count()
