@SuppressWarnings("unchecked")
    public T region(String region) {
        if (TextUtils.isEmpty(region)) {
            mRegion = null;
        } else {
            mRegion = region;
        }
        return (T) this;
    }
@ SuppressWarnings ( "unchecked" ) public T region ( String region ) { if ( TextUtils . isEmpty ( region ) ) { mRegion = null ; } else { mRegion = region ; } return ( T ) this ; }
@param region Region of the card.
@return {@link com.braintreepayments.api.models.BaseCardBuilder}