Fix datetime logic

list-branch-pr

@@ -24,7 +24,7 @@ import sys
 
 from argparse import ArgumentParser
 from collections import defaultdict
-from datetime import datetime
+from datetime import datetime, timezone
 
 from gql import Client, gql
 from gql.transport.requests import RequestsHTTPTransport
@@ -258,11 +258,11 @@ def main(args):
         # pr["updated_at"] can apparently be None sometimes, which breaks
         # sorting, so default to the empty string if so.
         for pull in sorted(prs, key=lambda pr: pr["updated_at"] or ""):
-            last_push_timestamp = \
-                int(datetime.fromisoformat(pull["updated_at"]).timestamp) \
-                if pull["updated_at"] else int(datetime.utcnow().timestamp)
+            updated_at = pull["updated_at"]
+            last_push = datetime.fromisoformat(updated_at) \
+                if updated_at else datetime.now(timezone.utc)
             print(group, pull["number"], pull["sha"], pull["build_config"],
-                  last_push_timestamp, sep="\t")
+                  int(last_push.timestamp()), sep="\t")
 
     if grouped["untested"]:
         # If there are untested PRs waiting, build all of them first.