Creating multiple topics

Sam suddenly became a black sheep because she is responsible for an onslaught of text messages and notifications to department directors.

No one will go to lunch with her anymore!

To fix this, she decided to create a general topic per department for routine notifications, and a critical topic for urgent notifications.

Managers will subscribe only to critical notifications, while supervisors can monitor general notifications.

For example, the streets department would have 'streets_general' and 'streets_critical' as topics.

She has initialized the SNS client and stored it in the sns variable.

Help Sam create a tiered topic structure... and have friends again!