Consider the voice mail application presented in in the below images

A new requirement is added to the system:

A mailbox owner can erase all messages in the queue from a specific phone number without having to listen to any of them. The mailbox owner would enter the sender's phone number on the phone keypad and the system will delete all messages sent from that phone.

(information not relevant for this question: assume the caller ID is available for all incoming messages)

a. Write the use case for this new feature. Add also one variant for an unsuccessful scenario. Make these scenarios integrate nicely with the other voice mail system use cases.

b. Write the sequence diagrams for the 2 new scenarios.

Telephone User enters dial extension findMailboX User speaks message record User hangs hangup up createx Message Figure 17 Sequence Diagram for Leaving a Message