from typing import Dict, Any
from datetime import datetime

class SessionManager:
    def __init__(self):
        self._sessions: Dict[int, Dict[str, Any]] = {}
    
    def get_session(self, user_id: int) -> Dict[str, Any]:
        return self._sessions.setdefault(user_id, {})
    
    def update_session(self, user_id: int, data: Dict[str, Any]) -> None:
        self._sessions[user_id] = {**self.get_session(user_id), **data}
    
    def clear_session(self, user_id: int) -> None:
        self._sessions.pop(user_id, None)