from graphviz import Digraph
g = Digraph('G', filename='Distrib', engine='dot')
g.edge("E", "E",label="0.3")
g.edge("A", "E",label="0.4")
g.edge("A", "A",label="0.6")
g.edge("E", "A",label="0.7")
g.format="svg"
g.render(view=True)