Restore 3.9 compatibility

.github/workflows/python-test.yml

@@ -36,7 +36,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-13, ubuntu-20.04, macos-latest, windows-2019]
-        py-version: ["3.10", "3.11", "3.12"]
+        py-version: ["3.9", "3.10", "3.11", "3.12"]
 
     steps:
       - uses: actions/checkout@v4

bw2io/extractors/ecospold1.py

@@ -3,7 +3,7 @@
 import os
 from io import StringIO
 from pathlib import Path
-from typing import Any, Union
+from typing import Any, Union, Optional
 
 import numpy as np
 import pyecospold
@@ -18,7 +18,7 @@
 from tqdm import tqdm
 
 
-def robust_text(root: etree.ElementBase, attribute: str) -> str | None:
+def robust_text(root: etree.ElementBase, attribute: str) -> Optional[str]:
     """Just because the spec says it must be there doesn't mean it will be."""
     try:
         return getattr(root, attribute).text

bw2io/importers/ecoinvent_lcia.py

@@ -1,6 +1,7 @@
 import functools
 import warnings
 from numbers import Number
+from typing import Optional
 
 from bw2data import Database, config
 
@@ -21,7 +22,7 @@ class EcoinventLCIAImporter(LCIAImporter):
 
     """
 
-    def __init__(self, biosphere_database: str | None = None):
+    def __init__(self, biosphere_database: Optional[str] = None):
         """Initialize an instance of EcoinventLCIAImporter.
 
         Defines strategies in ``__init__`` because ``config.biosphere`` is dynamic.

bw2io/importers/ecospold2.py

@@ -1,7 +1,7 @@
 from functools import partial
 from pathlib import Path
 from time import time
-from typing import Any
+from typing import Any, Optional
 
 from bw2data import Database, config
 
@@ -52,7 +52,7 @@ def __init__(
         self,
         dirpath: str,
         db_name: str,
-        biosphere_database_name: str | None = None,
+        biosphere_database_name: Optional[str] = None,
         extractor: Any = Ecospold2DataExtractor,
         use_mp: bool = True,
         signal: Any = None,

bw2io/importers/ecospold2_biosphere.py

@@ -1,6 +1,7 @@
 import json
 import os
 from pathlib import Path
+from typing import Optional
 
 from bw2data.utils import recursive_str_to_unicode
 from lxml import objectify
@@ -46,7 +47,7 @@ def __init__(
         self,
         name: str = "biosphere3",
         version: str = "3.9",
-        filepath: Path | None = None,
+        filepath: Optional[Path] = None,
     ):
         """
         Initialize the importer.