diff --git a/src/ifcopenshell-python/ifcopenshell/api/spatial/remove_container.py b/src/ifcopenshell-python/ifcopenshell/api/spatial/remove_container.py
index 2907fab1ff..b8417b3143 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/spatial/remove_container.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/spatial/remove_container.py
@@ -55,9 +55,7 @@ class Usecase:
             ifcopenshell.api.run("spatial.remove_container", model, product=wall)
         """
         self.file = file
-        self.settings = {"product": None}
-        for key, value in settings.items():
-            self.settings[key] = value
+        self.settings = {"product": product}
 
     def execute(self):
         contained_in_structure = self.settings["product"].ContainedInStructure
diff --git a/src/ifcopenshell-python/ifcopenshell/api/system/assign_system.py b/src/ifcopenshell-python/ifcopenshell/api/system/assign_system.py
index 03f947987d..ad4786c030 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/system/assign_system.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/system/assign_system.py
@@ -18,34 +18,7 @@
 
 import ifcopenshell
 import ifcopenshell.api
-
-
-ASSIGNABLE_DICT = {
-    "IfcZone": ("IfcZone", "IfcSpace", "IfcSpatialZone"),
-    "IfcBuiltSystem": (
-        "IfcBuiltElement",
-        "IfcFurnishingElement",
-        "IfcElementAssembly",
-        "IfcTransportElement",
-    ),
-    "IfcBuildingSystem": (
-        "IfcBuildingElement",
-        "IfcFurnishingElement",
-        "IfcElementAssembly",
-        "IfcTransportElement",
-    ),
-    "IfcDistributionSystem": ("IfcDistributionElement",),
-    "IfcStructuralAnalysisModel": ("IfcStructuralMember", "IfcStructuralConnection"),
-    "IfcSystem": ("IfcProduct",),
-    "IfcGroup": ("IfcObjectDefinition",),
-}
-
-
-def is_assignable(product, system) -> bool:
-    for assignable in ASSIGNABLE_DICT.get(system.is_a(), ()):
-        if product.is_a(assignable):
-            return True
-    return False
+import ifcopenshell.util.system
 
 
 class Usecase:
@@ -82,7 +55,7 @@ class Usecase:
     def execute(self):
         system = self.settings["system"]
         product = self.settings["product"]
-        if not is_assignable(product, system):
+        if not ifcopenshell.util.system.is_assignable(product, system):
             raise TypeError(f"You cannot assign an {product.is_a()} to an {system.is_a()}")
 
         if not self.settings["system"].IsGroupedBy:
diff --git a/src/ifcopenshell-python/ifcopenshell/util/system.py b/src/ifcopenshell-python/ifcopenshell/util/system.py
index 91dc441b32..630df515ef 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/system.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/system.py
@@ -17,6 +17,34 @@
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
 
+group_types = {
+    "IfcZone": ("IfcZone", "IfcSpace", "IfcSpatialZone"),
+    "IfcBuiltSystem": (
+        "IfcBuiltElement",
+        "IfcFurnishingElement",
+        "IfcElementAssembly",
+        "IfcTransportElement",
+    ),
+    "IfcBuildingSystem": (
+        "IfcBuildingElement",
+        "IfcFurnishingElement",
+        "IfcElementAssembly",
+        "IfcTransportElement",
+    ),
+    "IfcDistributionSystem": ("IfcDistributionElement",),
+    "IfcStructuralAnalysisModel": ("IfcStructuralMember", "IfcStructuralConnection"),
+    "IfcSystem": ("IfcProduct",),
+    "IfcGroup": ("IfcObjectDefinition",),
+}
+
+
+def is_assignable(product, system) -> bool:
+    for assignable in group_types.get(system.is_a(), ()):
+        if product.is_a(assignable):
+            return True
+    return False
+
+
 def get_system_elements(system):
     results = []
     for rel in system.IsGroupedBy:
diff --git a/src/ifcopenshell-python/test/api/unit/test_add_si_unit.py b/src/ifcopenshell-python/test/api/unit/test_add_si_unit.py
index 124bf7fa40..8ebc7234ad 100644
--- a/src/ifcopenshell-python/test/api/unit/test_add_si_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_add_si_unit.py
@@ -22,7 +22,7 @@ import ifcopenshell.api
 
 class TestAddSIUnit(test.bootstrap.IFC4):
     def test_run(self):
-        unit = ifcopenshell.api.run("unit.add_si_unit", self.file, unit_type="LENGTHUNIT", name="METRE", prefix="MILLI")
+        unit = ifcopenshell.api.run("unit.add_si_unit", self.file, unit_type="LENGTHUNIT", prefix="MILLI")
         assert unit.UnitType == "LENGTHUNIT"
         assert unit.Name == "METRE"
         assert unit.Prefix == "MILLI"
diff --git a/src/ifcopenshell-python/test/test_rules.py b/src/ifcopenshell-python/test/test_rules.py
index eda686c0a0..c6dba38927 100644
--- a/src/ifcopenshell-python/test/test_rules.py
+++ b/src/ifcopenshell-python/test/test_rules.py
@@ -5,6 +5,7 @@ import glob
 import pytest
 import tabulate
 
+import ifcopenshell.validate
 import ifcopenshell.express.rule_executor
 
 
@@ -40,4 +41,4 @@ def test_file(filename):
 
 
 if __name__ == "__main__":
-    pytest.main(["-sx", __file__])
\ No newline at end of file
+    pytest.main(["-sx", __file__])
diff --git a/src/ifcopenshell-python/test/test_write.py b/src/ifcopenshell-python/test/test_write.py
index 5ed2d69f19..e98a539dcb 100644
--- a/src/ifcopenshell-python/test/test_write.py
+++ b/src/ifcopenshell-python/test/test_write.py
@@ -26,7 +26,7 @@ TEST_FILE_DIR = Path("../../test/input/")
 
 
 class TestWrite:
-    def setup(self):
+    def setup_method(self):
         self.model = ifcopenshell.open(TEST_FILE_DIR / "WallInstance_IFC4Add2.ifc")
 
     def assert_model_is_written(self, filename, format=None, zipped=False):