public function set_email_restrictions( $emails = array() ) {
		$emails = array_filter( array_map( 'sanitize_email', array_map( 'strtolower', (array) $emails ) ) );
		foreach ( $emails as $email ) {
			if ( ! is_email( $email ) ) {
				$this->error( 'coupon_invalid_email_address', __( 'Invalid email address restriction', 'woocommerce' ) );
			}
		}
		$this->set_prop( 'email_restrictions', $emails );
	}