public function is_available( $package ) {
		$available = $this->is_enabled();

		// Country availability (legacy, for non-zone based methods).
		if ( ! $this->instance_id && $available ) {
			$countries = is_array( $this->countries ) ? $this->countries : array();

			switch ( $this->availability ) {
				case 'specific':
				case 'including':
					$available = in_array( $package['destination']['country'], array_intersect( $countries, array_keys( WC()->countries->get_shipping_countries() ) ) );
					break;
				case 'excluding':
					$available = in_array( $package['destination']['country'], array_diff( array_keys( WC()->countries->get_shipping_countries() ), $countries ) );
					break;
				default:
					$available = in_array( $package['destination']['country'], array_keys( WC()->countries->get_shipping_countries() ) );
					break;
			}
		}

		return apply_filters( 'woocommerce_shipping_' . $this->id . '_is_available', $available, $package, $this );
	}