Implement a Communication Handler with Exceptions

Context

You are tasked with building a single-line communication handler designed to connect exactly two Caller instances at any given time. The environment provides a Caller class, which includes at least a .name attribute, and an CommsHandlerABC abstract base class that defines the required interface for a communication handler.

Your primary goal is to implement a concrete subclass of CommsHandlerABC, named CommsHandler, that adheres to specific behavioral requirements, and to define a custom CommunicationException class.

Requirements

Classes to Implement

1. CommsHandler(CommsHandlerABC)
   • Methods:
     • connect(self, user1: Caller, user2: Caller) -> str
     • hangup(self, user1: Caller, user2: Caller) -> str
     • clear_all(self) -> None
   • Behavior for connect:
     • If user1 and user2 refer to the same Caller instance, raise CommunicationException with the exact message: "{user1.name} cannot connect with {user2.name}!"
     • If user1 and user2 are different Caller instances, but the communication line is already in use by another pair, raise CommunicationException with the message: "Connection in use. Please try later"
     • Otherwise (users are different and line is free), store the two connected users and return: "Connection established between {user1.name} and {user2.name}"
   • Behavior for hangup:
     • If user1 and user2 refer to the same Caller instance, raise CommunicationException with the message: "{user1.name} cannot hangup with {user2.name}"
     • If user1 and user2 are different Caller instances and are currently communicating via this handler, disconnect them and return: "{user1.name} and {user2.name} are disconnected"
     • If they are not currently communicating through this handler, raise CommunicationException with the message: "{user1.name} and {user2.name} not found in the communication channel"
   • Behavior for clear_all:
     • This method should clear the communication channel, effectively disconnecting any current users, without returning any value.
2. CommunicationException(Exception)
   • This custom exception class must accept an error message in its constructor and be raised as specified in the CommsHandler behaviors.

Important Notes

• When comparing Caller instances, use identity checks (is) rather than equality checks (e.g., user1 is user2 instead of user1.name == user2.name).
• The handler strictly supports only one active connection at a time.
• Include brief tests or usage examples to demonstrate the specified behaviors of your implementation.