cairosvg python 3

pygal/graph/base.py

@@ -205,8 +205,8 @@ class BaseGraph(object):
 
     def render_to_png(self, filename):
         import cairosvg
-        import StringIO
-        fakefile = StringIO.StringIO()
+        from io import BytesIO
+        fakefile = BytesIO()
         fakefile.write(self.render())
         fakefile.seek(0)
         cairosvg.surface.PNGSurface.convert(

pygal/test/test_graph.py

@@ -61,6 +61,6 @@ def test_render_to_png():
     line = Line()
     line.add('Serie 1', [1])
     line.render_to_png(file_name)
-    with open(file_name) as f:
+    with open(file_name, 'rb') as f:
         assert f.read()
     os.remove(file_name)