Fixed #28739 -- Fixed get_fixed_timezone() for negative timedeltas.

django/utils/timezone.py

@@ -58,7 +58,7 @@ utc = pytz.utc
 def get_fixed_timezone(offset):
     """Return a tzinfo instance with a fixed offset from UTC."""
     if isinstance(offset, timedelta):
-        offset = offset.seconds // 60
+        offset = offset.total_seconds() // 60
     sign = '-' if offset < 0 else '+'
     hhmm = '%02d%02d' % divmod(abs(offset), 60)
     name = sign + hhmm