diff --git a/dirty_equals/_datetime.py b/dirty_equals/_datetime.py
index e52ef04..fb30aae 100644
--- a/dirty_equals/_datetime.py
+++ b/dirty_equals/_datetime.py
@@ -127,14 +127,6 @@ def approx_equals(self, other: datetime, delta: timedelta) -> bool:
             return True
 
 
-def _zoneinfo(tz: str) -> ZoneInfo:
-    """
-    Instantiate a `ZoneInfo` object from a string, falling back to `pytz.timezone` when `ZoneInfo` is not available
-    (most likely on Python 3.8 and webassembly).
-    """
-    return ZoneInfo(tz)
-
-
 class IsNow(IsDatetime):
     """
     Check if a datetime is close to now, this is similar to `IsDatetime(approx=datetime.now())`,
@@ -180,7 +172,7 @@ def __init__(
         ```
         """
         if isinstance(tz, str):
-            tz = _zoneinfo(tz)
+            tz = ZoneInfo(tz)
 
         self.tz = tz
 
diff --git a/tests/test_datetime.py b/tests/test_datetime.py
index 1ba16f3..7676033 100644
--- a/tests/test_datetime.py
+++ b/tests/test_datetime.py
@@ -1,3 +1,4 @@
+import sys
 from datetime import date, datetime, timedelta, timezone
 from unittest.mock import Mock
 
@@ -5,10 +6,12 @@
 
 from dirty_equals import IsDate, IsDatetime, IsNow, IsToday
 
-try:
+if sys.version_info >= (3, 9):
     from zoneinfo import ZoneInfo
-except ImportError:
-    from backports.zoneinfo import ZoneInfo
+else:
+    # This code block is due to a typing issue with backports.zoneinfo package:
+    # https://github.com/pganssle/zoneinfo/issues/125
+    from backports.zoneinfo._zoneinfo import ZoneInfo
 
 
 @pytest.mark.parametrize(