Runtime warning for tier indices out of range

src/aligned_textgrid/mixins/mixins.py

@@ -166,8 +166,7 @@ def get_tierwise(
             in the initial position within its subset list, this will not be the same as
             `.prev` 
 
-        This will raise an ordinary IndexError if the relative index exceeds the length
-        of the tier.
+        If the provided index is out of range, this will generate RuntimeWarning.
 
         Args:
             idx (int, optional): 
@@ -177,11 +176,11 @@ def get_tierwise(
         Returns:
             (SequenceInterval|SequencePoint): The entry at the relative index
         """
-        if not self.intier is None:
-            return self.intier[self.tier_index + idx]
-        else:
+        if self.inter is None:
             return None
 
+        return self.intier[self.tier_index + idx]
+
     def return_praatio(self)->Interval|Point:
         """Return the correct `praatio` class.
 

src/aligned_textgrid/sequences/tiers.py

@@ -128,6 +128,17 @@ def __build_sequence_list(self)->None:
 
 
     def __getitem__(self, idx:int)->SequenceInterval:
+        if idx >= len(self.sequence_list) or idx < -len(self.sequence_list):
+            warnings.warn(
+                (
+                    f"Provided index ({idx}) "
+                    f"to object {self.__class__.__name__} "
+                    "is out of range."
+                ),
+                category = RuntimeWarning,
+            )
+            return None
+
         return self.sequence_list[idx]
 
     def __len__(self)->int:

tests/test_tiers/test_SequenceTier.py

@@ -47,10 +47,12 @@ def test_default_xmin(self):
     def test_default_xmax(self):
         assert self.default_tier.xmax is None
 
-    def test_default_getitme(self):
-        with pytest.raises(IndexError):
+    def test_default_getitem(self):
+        with pytest.warns(RuntimeWarning):
             _ = self.default_tier[0]
 
+
+
 class TestTierMaking:
 
     def test_class_setting(self):