diff --git a/src/ifcopenshell-python/ifcopenshell/api/sequence/assign_product.py b/src/ifcopenshell-python/ifcopenshell/api/sequence/assign_product.py
index afc29f5d64..4437913ffc 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/sequence/assign_product.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/sequence/assign_product.py
@@ -16,7 +16,7 @@ class Usecase:
         if self.settings["related_object"].HasAssignments:
             for assignment in self.settings["related_object"].HasAssignments:
                 if (
-                    assignment.is_a("IfclRelAssignsToProduct")
+                    assignment.is_a("IfcRelAssignsToProduct")
                     and assignment.RelatingProduct == self.settings["relating_product"]
                 ):
                     return
diff --git a/src/ifcopenshell-python/test/api/library/test_unassign_reference.py b/src/ifcopenshell-python/test/api/library/test_unassign_reference.py
index 4e2b651928..6c31a05c08 100644
--- a/src/ifcopenshell-python/test/api/library/test_unassign_reference.py
+++ b/src/ifcopenshell-python/test/api/library/test_unassign_reference.py
@@ -6,7 +6,6 @@ class TestUnassignReference(test.bootstrap.IFC4):
     def test_unassigning_a_reference(self):
         reference = self.file.createIfcLibraryReference()
         product = self.file.createIfcWall()
-        product2 = self.file.createIfcWall()
         ifcopenshell.api.run("library.assign_reference", self.file, product=product, reference=reference)
         ifcopenshell.api.run("library.unassign_reference", self.file, product=product, reference=reference)
         assert len(self.file.by_type("IfcRelAssociatesLibrary")) == 0
diff --git a/src/ifcopenshell-python/test/api/sequence/test_assign_product.py b/src/ifcopenshell-python/test/api/sequence/test_assign_product.py
new file mode 100644
index 0000000000..d2777a4bf2
--- /dev/null
+++ b/src/ifcopenshell-python/test/api/sequence/test_assign_product.py
@@ -0,0 +1,20 @@
+import test.bootstrap
+import ifcopenshell.api
+
+
+class TestAssignProduct(test.bootstrap.IFC4):
+    def test_assigning_a_product(self):
+        wall = self.file.createIfcWall()
+        task = self.file.createIfcTask()
+        task2 = self.file.createIfcTask()
+        ifcopenshell.api.run("sequence.assign_product", self.file, relating_product=wall, related_object=task)
+        assert wall.ReferencedBy[0].RelatedObjects == (task,)
+        ifcopenshell.api.run("sequence.assign_product", self.file, relating_product=wall, related_object=task2)
+        assert wall.ReferencedBy[0].RelatedObjects == (task, task2)
+
+    def test_not_assigning_twice(self):
+        wall = self.file.createIfcWall()
+        task = self.file.createIfcTask()
+        ifcopenshell.api.run("sequence.assign_product", self.file, relating_product=wall, related_object=task)
+        ifcopenshell.api.run("sequence.assign_product", self.file, relating_product=wall, related_object=task)
+        assert wall.ReferencedBy[0].RelatedObjects == (task,)
diff --git a/src/ifcopenshell-python/test/api/sequence/test_unassign_product.py b/src/ifcopenshell-python/test/api/sequence/test_unassign_product.py
new file mode 100644
index 0000000000..4ca994143c
--- /dev/null
+++ b/src/ifcopenshell-python/test/api/sequence/test_unassign_product.py
@@ -0,0 +1,11 @@
+import test.bootstrap
+import ifcopenshell.api
+
+
+class TestUnassignProduct(test.bootstrap.IFC4):
+    def test_unassigning_a_product(self):
+        wall = self.file.createIfcWall()
+        task = self.file.createIfcTask()
+        ifcopenshell.api.run("sequence.assign_product", self.file, relating_product=wall, related_object=task)
+        ifcopenshell.api.run("sequence.unassign_product", self.file, relating_product=wall, related_object=task)
+        assert len(self.file.by_type("IfcRelAssignsToProduct")) == 0