public function isSourceCloneable( $metadata_license ) {
		$restrictive_licenses = [
			'https://creativecommons.org/licenses/by-nd/4.0/',
			'https://creativecommons.org/licenses/by-nc-nd/4.0/',
			'https://choosealicense.com/no-license/',
		];

		if ( is_array( $metadata_license ) ) {
			$license_url = $metadata_license['url'];
		} else { // Backwards compatibility.
			$license_url = $metadata_license;
		}

		$license_url = trailingslashit( trim( $license_url ) );
		if ( ! empty( $this->sourceBookId ) ) {
			if ( $this->isSuperAdmin ) {
				return true; // Network administrators can clone local books no matter how they're licensed
			} elseif ( ! in_array( $license_url, $restrictive_licenses, true ) ) {
				return true; // Anyone can clone local books that aren't restrictively licensed
			} else {
				return false;
			}
		} elseif ( in_array( $license_url, $restrictive_licenses, true ) ) {
			return false; // No one can clone global books that are restrictively licensed
		}
		return true;
	}