requirements: Add backports.datetime_fromisoformat for Py<3.11.

Co-authored-by: Anders Kaseorg <[email protected]>

Author: Niloth-p

pyproject.toml

@@ -60,6 +60,7 @@ warn_unreachable = true
 [[tool.mypy.overrides]]
 module = [
     "apiai.*",
+    "backports.datetime_fromisoformat.*",
     "feedparser.*",
     "gitlint.*",
     "google.auth.*",

zulip/setup.py

@@ -64,6 +64,7 @@ def recur_expand(target_root: Any, dir: Any) -> Generator[Tuple[str, List[str]],
         ],
     },
     install_requires=[
+        "backports-datetime-fromisoformat; python_version < '3.11'",
         "requests[security]>=0.12.1",
         "distro",
         "click",

zulip/zulip/__init__.py

@@ -35,6 +35,13 @@
 # Ensure the Python version is supported
 assert sys.version_info >= (3, 6)
 
+if sys.version_info < (3, 11):
+    from backports.datetime_fromisoformat import (
+        datetime_fromisoformat as datetime_fromisoformat,  # noqa: PLC0414
+    )
+else:
+    datetime_fromisoformat = datetime.fromisoformat
+
 logger = logging.getLogger(__name__)
 
 API_VERSTRING = "v1/"