Write documentation for resource API module

src/ifcopenshell-python/ifcopenshell/api/resource/add_resource_quantity.py

@@ -20,11 +20,49 @@ import ifcopenshell.util.element
 
 
 class Usecase:
-    def __init__(self, file, **settings):
+    def __init__(self, file, resource=None, ifc_class="IfcQuantityCount"):
+        """Adds a quantity to a resource
+
+        The quantity of a resource represents the "unit quantity" of that
+        resource. For example, labour might be hired on a daily basis (8 hours).
+        There are different types of quantities (e.g. volume, count, or time).
+        Which quantity is used depends on the type of resource.  Material
+        resources may be quantified in terms of length, area, volume, or weight.
+        Equipment and labour resources are quantified in terms of time. Products
+        resources are quantified in terms of counts.
+
+        This base quantity is then used in other calculations.
+
+        :param resource: The IfcConstructionResource to add a quantity to.
+        :type resource: ifcopenshell.entity_instance.entity_instance
+        :param ifc_class: The type of quantity to add, chosen from
+            IfcQuantityArea (for material), IfcQuantityCount (for products),
+            IfcQuantityLength (for material), IfcQuantityTime (for equipment or
+            labour), IfcQuantityVolume (for material), and IfcQuantityWeight
+            (for material).
+        :type ifc_class: str,optional
+        :return: The newly created quantity depending on the IFC class
+        :rtype: ifcopenshell.entity_instance.entity_instance
+
+        Example::
+
+            # Add our own crew
+            crew = ifcopenshell.api.run("resource.add_resource", model, ifc_class="IfcCrewResource")
+
+            # Add some labour to our crew.
+            labour = ifcopenshell.api.run("resource.add_resource", model,
+                parent_resource=crew, ifc_class="IfcLaborResource")
+
+            # Labour resource is quantified in terms of time.
+            ifcopenshell.api.run("resource.add_resource_quantity", model,
+                resource=labour, ifc_class="IfcQuantityTime")
+
+            # Store the time used in hours
+            ifcopenshell.api.run("resource.edit_resource_quantity", model,
+                physical_quantity=time, attributes={"TimeValue": 8.0})
+        """
         self.file = file
-        self.settings = {"resource": None, "ifc_class": "IfcQuantityCount"}
-        for key, value in settings.items():
-            self.settings[key] = value
+        self.settings = {"resource": resource, "ifc_class": ifc_class}
 
     def execute(self):
         quantity = self.file.create_entity(self.settings["ifc_class"], Name="Unnamed")