class AvitoAPIError(Exception):
    """Base exception for all Avito API errors."""
    pass

class AvitoAuthError(AvitoAPIError):
    """Raised when authentication fails (HTTP 401 or 403)."""
    pass

class AvitoRateLimitError(AvitoAPIError):
    """Raised when API rate limits are exceeded (HTTP 429)."""
    pass

class AvitoBadRequestError(AvitoAPIError):
    """Raised when API returns HTTP 400."""
    pass

class AvitoNotFoundError(AvitoAPIError):
    """Raised when API returns HTTP 404."""
    pass