Add support for writing graphml files from nx dialect

CHANGELOG.md

@@ -7,6 +7,7 @@
     -   Added `grand.DiGraph` convenience wrapper for directed graphs
 -   Dialects
     -   Expanded Networkit dialect test coverage
+    -   Added support for exporting NetworkX graphs by adding `graph` attribute
 
 ## **0.4.2** (May 7, 2022)
 

grand/dialects/__init__.py

@@ -161,6 +161,10 @@ def _pred(self):
         """
         return _GrandAdjacencyView(self, "pred")
 
+    @property
+    def graph(self):
+        return {}
+
     def in_degree(self, nbunch=None):
         return self.parent.backend.in_degrees(nbunch)
 

grand/dialects/test_dialect.py

@@ -1,3 +1,4 @@
+import io
 import unittest
 
 from .. import Graph
@@ -89,6 +90,11 @@ def test_nx_edges(self):
         self.assertEqual(dict(G.edges()), dict(H.edges()))
         self.assertEqual(list(G.edges["1", "2"]), list(H.edges["1", "2"]))
 
+    def test_nx_export(self):
+        gg = Graph()
+        f = io.BytesIO()
+        nx.write_graphml(gg.nx, f)
+
 
 class TestNetworkitDialect(unittest.TestCase):
     def test_add_verts(self):