Ios 无法将类型字符串的值转换为指定的类型NSManagedObjectContext Swift 4

我需要帮助。从Swift 2.3->3.2转换时，我收到以下错误。我无法解决此错误

错误：无法将类型字符串的值转换为指定的类型NSManagedObjectContext

下面是我的代码，我面临一些问题

class FileManager {
    class func directoryForPersistentStorage(_ directoryName: String) -> Foundation.URL {
        var urlToReturn: Foundation.URL!

        let libraryDirectory = (NSSearchPathForDirectoriesInDomains(.libraryDirectory, .userDomainMask, true) as [String]).first
        if let cLibraryDirectory = libraryDirectory {
            let expectedDirectoryPath = (cLibraryDirectory as NSString).appendingPathComponent(directoryName)
            let fileManager = Foundation.FileManager.default
            var isDirectory = ObjCBool(false)
            if (!fileManager.fileExists(atPath: expectedDirectoryPath, isDirectory: &isDirectory) || !isDirectory.boolValue) {
                do {
                    try fileManager.createDirectory(atPath: expectedDirectoryPath, withIntermediateDirectories: true, attributes: nil)
                } catch _ {
                }
            }
            urlToReturn = URL(context: expectedDirectoryPath) // Above mentioned #Error is Here

            if fileManager.fileExists(atPath: expectedDirectoryPath) {
                do {

                    try urlToReturn.setTemporaryResourceValue(true as AnyObject?, forKey: URLResourceKey.isExcludedFromBackupKey)

                } catch _ {
                }
            }
        }
        return urlToReturn
    }

    class func persistentFileURL(_ name: String, enclosingDirectoryName: String) -> Foundation.URL {
        let directoryURL = self.directoryForPersistentStorage(enclosingDirectoryName)
        let urlPath = directoryURL.path
        let filePath: String = (urlPath as NSString).appendingPathComponent(name)

        return URL(context: filePath) // Above mentioned #Error is Here
    }
}

错误1:无法将字符串类型的值转换为指定的NSManagedObjectContext类型**

注意：URL是单独声明的类，用于处理此：&

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请帮帮我。我对iOS很陌生。无法理解这类错误。

在哪一行出现错误？标有此注释的行=>//上面提到的#错误在这里只有两个相同的错误。在两条线上你检查这个是的我检查了那个。。。我们已经解决了这个错误。但这似乎更成问题。