func GetStringPolicy(d *schema.ResourceData, key string) *types.StringPolicy {
	v, e := d.GetOkExists(key)
	if e {
		return StringPolicy(v.(string))
	}
	return nil
}
func GetStringPolicy(d *schema.ResourceData, key string) *types.StringPolicy {
	v, e := d.GetOkExists(key)
	if e {
		return StringPolicy(v.(string))
	}
	return nil
}
// GetStringPolicy reads a ResourceData and returns an appropriate StringPolicy
// for the state of the definition. nil is returned if it does not exist.