fix: some more error

cve_bin_tool/vex_manager/generate.py

@@ -4,6 +4,7 @@
 from datetime import datetime
 from logging import Logger
 from pathlib import Path
+from typing import Optional
 
 from lib4sbom.data.vulnerability import Vulnerability
 from lib4vex.generator import VEXGenerator
@@ -40,8 +41,8 @@ def __init__(
         filename: str,
         vextype: str,
         all_cve_data: dict[ProductInfo, CVEData],
-        sbom: str | None = None,
-        logger: Logger | None = None,
+        sbom: Optional[str] = None,
+        logger: Optional[Logger] = None,
         validate: bool = True,
     ):
         self.product = product