WP_Theme::is_allowed() WordPress Method

	public function is_allowed( $check = 'both', $blog_id = null ) {
		if ( ! is_multisite() ) {
			return true;
		}

		if ( 'both' === $check || 'network' === $check ) {
			$allowed = self::get_allowed_on_network();
			if ( ! empty( $allowed[ $this->get_stylesheet() ] ) ) {
				return true;
			}
		}

		if ( 'both' === $check || 'site' === $check ) {
			$allowed = self::get_allowed_on_site( $blog_id );
			if ( ! empty( $allowed[ $this->get_stylesheet() ] ) ) {
				return true;
			}
		}

		return false;
	}