diff --git a/pyproject.toml b/pyproject.toml
index 6bf5967c8e..930d8764b1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -113,7 +113,9 @@ invalid-assignment = "ignore"
 invalid-parameter-default = "ignore"
 missing-override-decorator = "ignore"
 invalid-yield = "ignore"
+unsound-yield = "ignore"
 invalid-return-type = "ignore"
+unsound-return-statement = "ignore"
 non-callable-init-subclass = "ignore"
 not-iterable = "ignore"
 possibly-missing-attribute = "ignore"
diff --git a/requirements-tools.txt b/requirements-tools.txt
index 1388c7c518..e8c204d040 100644
--- a/requirements-tools.txt
+++ b/requirements-tools.txt
@@ -1,5 +1,5 @@
 black==26.3.1
 ruff==0.16.0
 poethepoet
-ty==0.0.63
+ty==0.0.72
 gersemi==0.28.0
diff --git a/src/ifcopenshell-python/ifcopenshell/api/alignment/create_as_polyline.py b/src/ifcopenshell-python/ifcopenshell/api/alignment/create_as_polyline.py
index 05e2262d4a..a86d1d16bc 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/alignment/create_as_polyline.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/alignment/create_as_polyline.py
@@ -47,6 +47,7 @@ def _create_layout(file: ifcopenshell.file, alignment: entity_instance, points:
 
     start_dist_along = 0.0
     gradient = None
+    dir = None
     for p1, p2 in zip(points, points[1:]):
         x1, y1, z1 = p1.Coordinates
         x2, y2, z2 = p2.Coordinates
@@ -86,6 +87,7 @@ def _create_layout(file: ifcopenshell.file, alignment: entity_instance, points:
         start_dist_along += length
 
     # zero length segment
+    assert dir is not None
     hsegment = file.createIfcAlignmentSegment(
         ifcopenshell.guid.new(),
         DesignParameters=file.createIfcAlignmentHorizontalSegment(