diff --git a/codegen/templates/transform_2d.pyx b/codegen/templates/transform_2d.pyx
index c45485b..bfc1499 100644
--- a/codegen/templates/transform_2d.pyx
+++ b/codegen/templates/transform_2d.pyx
@@ -245,13 +245,14 @@ cdef class Transform2D:
         t.oy = self.muly(other.ox, other.oy)
         return t
 
-    def __imatmul__(self, Transform2D other) -> None:
+    def __imatmul__(self, Transform2D other) -> Transform2D:
         self.xx = other.tdotx(self.xx, self.xy)
         self.xy = other.tdoty(self.xx, self.xy)
         self.yx = other.tdotx(self.yx, self.yy)
         self.yy = other.tdoty(self.yx, self.yy)
         self.ox = other.mulx(self.ox, self.oy)
         self.oy = other.muly(self.ox, self.oy)
+        return self
 
     cdef inline py_float _determinant(self) noexcept:
         return self.xx * self.yy - self.xy * self.yx
diff --git a/codegen/templates/transform_3d.pyx b/codegen/templates/transform_3d.pyx
index c12fb1e..f8002a2 100644
--- a/codegen/templates/transform_3d.pyx
+++ b/codegen/templates/transform_3d.pyx
@@ -366,7 +366,7 @@ cdef class Transform3D:
         t.oz = self.mulz(other.ox, other.oy, other.oz)
         return t
 
-    def __imatmul__(self, Transform3D other) -> None:
+    def __imatmul__(self, Transform3D other) -> Transform3D:
         self.xx = other.tdotx(self.xx, self.xy, self.xz)
         self.xy = other.tdoty(self.xx, self.xy, self.xz)
         self.xz = other.tdotz(self.xx, self.xy, self.xz)
@@ -379,6 +379,7 @@ cdef class Transform3D:
         self.ox = other.mulx(self.ox, self.oy, self.oz)
         self.oy = other.muly(self.ox, self.oy, self.oz)
         self.oz = other.mulz(self.ox, self.oy, self.oz)
+        return self
 
     cdef inline py_float _determinant(self) noexcept:
         return (self.xx * (self.yy * self.zz - self.yz * self.zy) -
diff --git a/pyproject.toml b/pyproject.toml
index ec8a427..7bd712e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ requires = ["setuptools", "cython"]
 
 [project]
 name = "gdmath"
-version = "1.4.0"
+version = "1.4.1"
 description = "GdMath: a fast math library for game development"
 readme = "README.md"
 requires-python = ">= 3.9"