Add docs for attribute API

src/ifcopenshell-python/ifcopenshell/api/attribute/edit_attributes.py

@@ -20,11 +20,30 @@ import ifcopenshell.api
 
 
 class Usecase:
-    def __init__(self, file, **settings):
+    def __init__(self, file, product=None, attributes=None):
+        """Edit the attributes of a product
+
+        All IFC entities have attributes. Normally they can be edited directly,
+        by simply assigning a new value to them. In some scenarios, you may wish
+        to also ensure that ownership history is updated. This function provides
+        that convenience.
+
+        :param product: The product you want to edit. This may be any rooted IFC
+            entity.
+        :type product: ifcopenshell.entity_instance
+        :param attributes: a dictionary of attribute names and values.
+        :type attributes: dict, optional
+        :return: None
+        :rtype: None
+
+        Example::
+
+            element = ifcopenshell.api.run("root.create_entity", model, ifc_class="IfcWall")
+            ifcopenshell.api.run("attribute.edit_attributes", model,
+                product=element, attributes={"Name": "Waldo"})
+        """
         self.file = file
-        self.settings = {"product": None, "attributes": {}}
-        for key, value in settings.items():
-            self.settings[key] = value
+        self.settings = {"product": product, "attributes": attributes or {}}
 
     def execute(self):
         for name, value in self.settings["attributes"].items():