--- a/wsgraph/model.py	Sat Dec 15 23:22:19 2012 -0800
+++ b/wsgraph/model.py	Mon Dec 24 22:57:02 2012 -0800
@@ -38,6 +38,13 @@
     def edges(self):
         """returns a list of all edges"""
 
+    @abstractmethod
+    def delete(self, node1, node2=None):
+        """
+        delete a node or edge if node2 is given
+        If a node is deleted, all edges to it should be deleted
+        """
+
     def __call__(self):
         """
         returns JSGN format of graph:
@@ -73,6 +80,13 @@
             key1, key2 = key
             self.edge(key1, key2, value)
 
+    def __delitem__(self, key):
+        if isinstance(key, basestring) or (not isiterable(key)):
+            self.delete(key)
+        else:
+            key1, key2 = key
+            self.delete(key1, key2)
+
     def __contains__(self, key):
         """
         if key is ..., returns if that node is in the graph