1 files changed, 37 insertions, 0 deletions
diff --git a/src-py/model/graph.py b/src-py/model/graph.py
new file mode 100644
index 00000000..9891c4ef
--- /dev/null
+++ b/src-py/model/graph.py
@@ -0,0 +1,37 @@
+class Attribute_Diff():
+    """
+    Represents a change to note attributes, where nodes can represent
+    either logical nodes or logical links, and attributes can be added,
+    changed or removed
+    """
+    pass
+
+class Topo_Diff():
+    """
+    Represents a change to the graph topology
+    """
+
+    def __init__(self, link_set_rm=[],
+                        node_set_rm=[],
+                        node_set_add=[],
+                        link_set_add=[]):
+        self.link_set_rm = link_set_rm
+        self.node_set_rm = node_set_rm
+        self.node_set_add = node_set_add
+        self.link_set_add = link_set_add
+
+    @property
+    def link_set_rm(self):
+        return self.link_set_rm
+
+    @property
+    def node_set_rm(self):
+        return self.node_set_rm
+
+    @property
+    def link_set_add(self):
+        return self.link_set_add
+
+    @property
+    def node_set_add(self):
+        return self.node_set_add