WidgetPlantProvider.swift

extension WidgetPlantProvider {
    static let sharedDataFileURL: URL = {
        let appGroupIdentifier = "group.com.company.appname.widget"
        if let url = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: appGroupIdentifier) {
            return url.appendingPathComponent("Plants.plist")
        }
        else {
            preconditionFailure("Expected a valid app group container")
        }
    }()
}