A whole bunch of new usecases for managing IFC library information and references

src/ifcopenshell-python/ifcopenshell/api/library/unassign_reference.py

@@ -0,0 +1,19 @@
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {"reference": None, "product": None}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        rels = self.settings["reference"].LibraryRefForObjects
+        if not rels:
+            return
+        for rel in rels:
+            if self.settings["product"] in rel.RelatedObjects:
+                if len(rel.RelatedObjects) == 1:
+                    self.file.remove(rel)
+                    continue
+                related_objects = list(rel.RelatedObjects)
+                related_objects.remove(self.settings["product"])
+                rel.RelatedObjects = related_objects