Added sfg and show_sfg methods

Allows displaying SFG:s

b_asic/signal_flow_graph.py

@@ -885,6 +885,9 @@ class SFG(AbstractOperation):
                     dg.node(op.graph_id)
         return dg
 
+    def _repr_svg_(self):
+        return self.sfg()._repr_svg_()
+
     def show_sfg(self, format=None, show_id=False, engine=None) -> None:
         """
         Shows a visual representation of the SFG using the default system viewer.