Implement a Communication Handler with Exceptions

Context

You are building a single-line communication handler that can connect exactly two Caller instances at a time. The environment already provides:

• Caller: a class with at least a .name attribute (assume implemented elsewhere).
• CommsHandlerABC: an abstract base class specifying the interface for a communication handler.

Your task is to implement a concrete CommsHandler subclass that enforces the specified behaviors and to define a custom CommunicationException.

Requirements

Classes to Implement

1. CommsHandler(CommsHandlerABC)
   • Methods to implement:
     • connect(self, user1: Caller, user2: Caller) -> str
     • hangup(self, user1: Caller, user2: Caller) -> str
     • clear_all(self) -> None
   • Behavior:
     • connect:
       • If user1 is user2, raise CommunicationException with the exact message: "{user1.name} cannot connect with {user2.name}!"
       • If user1 and user2 are different and the communication line is already in use, raise CommunicationException with: "Connection in use. Please try later"
       • Otherwise, store the two connected users and return: "Connection established between {user1.name} and {user2.name}"
     • hangup:
       • If user1 is user2, raise CommunicationException with: "{user1.name} cannot hangup with {user2.name}"
       • If user1 and user2 are different and are currently communicating, disconnect them and return: "{user1.name} and {user2.name} are disconnected"
       • If they are not communicating, raise CommunicationException with: "{user1.name} and {user2.name} not found in the communication channel"
     • clear_all:
       • Clear the communication channel regardless of current users (no return value).
2. CommunicationException(Exception)
   • Accepts an error message in its constructor and is raised as specified.

Notes

• Use identity checks (is) when comparing callers (i.e., same object instance), not name equality.
• The handler supports only one active connection at a time.
• Provide brief tests or usage examples demonstrating the specified behaviors.