Write API documentation for control module

src/ifcopenshell-python/ifcopenshell/api/control/unassign_control.py

@@ -21,14 +21,38 @@ import ifcopenshell.api
 
 
 class Usecase:
-    def __init__(self, file, **settings):
+    def __init__(self, file, relating_control=None, related_object=None):
+        """Unassigns a planning control or constraint to an object
+
+        :param relating_control: The IfcControl entity that is creating the
+            control or constraint
+        :type relating_control: ifcopenshell.entity_instance.entity_instance
+        :param related_object: The IfcObjectDefinition that is being controlled
+        :type related_object: ifcopenshell.entity_instance.entity_instance
+        :return: If the control still is related to other objects, the
+            IfcRelAssignsToControl is returned, otherwise None.
+        :rtype: ifcopenshell.entity_instance.entity_instance, None
+
+        Example::
+
+            # Let's relate a cost item and a product
+            wall = ifcopenshell.api.run("root.create_entity", model, ifc_class="IfcWall")
+            schedule = ifcopenshell.api.run("cost.add_cost_schedule", model)
+            cost_item = ifcopenshell.api.run("cost.add_cost_item", model,
+                cost_schedule=schedule)
+            ifcopenshell.api.run("control.assign_control", model,
+                relating_control=cost_item, related_object=wall)
+
+            # And now let's change our mind
+            ifcopenshell.api.run("control.unassign_control", model,
+                relating_control=cost_item, related_object=wall)
+        """
+
         self.file = file
         self.settings = {
-            "relating_control": None,
-            "related_object": None,
+            "relating_control": relating_control,
+            "related_object": related_object,
         }
-        for key, value in settings.items():
-            self.settings[key] = value
 
     def execute(self):
         for rel in self.settings["related_object"].HasAssignments or []: