             publication.links.append(link)
         }
         // FIXME: wait SO answer
-        let remainingProperties = properties.filter{$0 != "cover-image" && $0 != "nav"}
-        
+        let remainingProperties = properties.filter { $0 != "cover-image" && $0 != "nav" }
+
         link.properties.append(contentsOf: remainingProperties)
         // TODO: rendition properties
     }

    ///   - element: The XML element to parse
    ///   - doc: The OPF XML document being parsed
    ///   - metadata: The metadata to which to add the contributor
    private func parseContributor(from element: AEXMLElement,
                                  in document: AEXMLDocument,
                                  to metadata: Metadata) {
        let metadataElement = document.root["metadata"]

    /// - Parameter metadata: The `<metadata>` element
    /// - Returns: The content of the `<dc:title>` element, `nil` if the element
    ///             wasn't found
    internal func parseMainTitle(from metadata: AEXMLElement) -> String? {
        // Return if there isn't any `<dc:title>` element
        guard let titles = metadata["dc:title"].all else {
            return nil
