NSManagedObject+Ext.swift

import CoreData

extension NSManagedObject {
    convenience public init(insertInto context: NSManagedObjectContext?) {
        let name = String(describing: type(of: self))
        let entity = NSEntityDescription.entity(forEntityName: name, in: context!)
        self.init(entity: entity!, insertInto: context)
    }
}

to create a managed object you simply do:

let sensor = Sensor(moc)