Design a Lottery System with the following functions. I probably failed this interview, but I can manage to get all of these in O(1) time except the drawWinner.\n\nHaving the name as the key is what my issue is, if the identifier were a number, this would be easy, anyone have any ideas?\n\n```\ndef registerContestant( name: str ):\n    pass\n\ndef unregisterContestant( name: str ):\n    pass\n\ndef isRegistered( name: str ):\n    pass\n\ndef changeName( oldName : str, newName : str):\n    pass\n\ndef drawWinner():\n    pass\n\n```

Design a Lottery System with the following functions. I probably failed this interview, but I can manage to get all of these in O(1) time except the drawWinner.