1from __future__ import annotations
 2
 3
 4class SessionNotAvailable(Exception):
 5    """
 6    Raised when attempting to access a session that hasn't been set up.
 7
 8    This typically occurs when:
 9    - SessionMiddleware hasn't been called yet (e.g., during early middleware processing)
10    - An error occurred before SessionMiddleware could run
11    - A request is being processed outside the normal middleware chain
12    """
13
14    pass