def unique_value(domain):
    """Return if unique, the field and the value"""
    if isinstance(domain, list) and len(domain) == 1:
        domain, = domain
        name = domain[0]
        value = domain[2]
        count = 0
        if len(domain) == 4 and name[-3:] == '.id':
            count = 1
            model = domain[3]
            value = [model, value]
        if name.count('.') == count and domain[1] == '=':
            return True, domain[1], value
    return False, None, None
