Extensible Multi-Channel Notification System Design

amazon Design a notification system that sends notifications to different channels, and each channel supports different types of notifications, such as SMS, email, and push notifications. Requirements Support sending notifications to multiple channels, including but not limited to: SMS Email Push Notification Each channel should have different configurations and notification strategies. The system should be easily extensible to support new types of notifications and channels. Provide test cases to verify the correctness of the system design and functionality. Example Input SMSChannel, Test Notification