 	public func animate(to: T, completion: @escaping (_ animator: YapAnimator, _ wasInterrupted: Bool) -> Void = { _, _ in }) {
 
 		toValue = to
-		satisfyCompletion(withSuccess: false, newCompletion: completion)
+		fulfillCompletion(success: false, newCompletion: completion)
 	}
 
 	public func instant(to: T) {
 
-		satisfyCompletion(withSuccess: false)
+		fulfillCompletion(success: false)
 		needsUpdate = false
 		toValue = to
 		updateInstant()

		return isInMotion
	}

	func satisfyCompletion(withSuccess success: Bool, newCompletion: @escaping (_ animator: YapAnimator, _ wasInterrupted: Bool) -> Void = { _, _ in }) {

		let completionCopy = self.completion
		completion = newCompletion

			case .updated:
				eachFrame(self)
			case .completed:
				fulfillCompletion(success: true)
			case .cancelled:
				fulfillCompletion(success: false)
			}
			observer?.didChangeState(animator: self)
		}
