Cannot extend existing class by inherintance when using subgraph about graphviz HOT 3 CLOSED

from graphviz import Graph

class ClusterGraph(Graph):
    def __init__(self, name):
        super(ClusterGraph, self).__init__('cluster_' + name)

g1 = Graph()
g2 = ClusterGraph('spam')
g1.subgraph(g2)
print g1.source + g2.source
graph {
    subgraph cluster_spam {
    }
}
graph cluster_spam {
}

import graphviz

class GraphArea(graphviz.Digraph):
    def __init__(self, **kwargs):
        super().__init__(name='graph', format='svg',
                         graph_attr=dict(rankdir='LR'),
                         node_attr=dict(shape='box'))
        with self.subgraph(name="cluster_0") as c:
            print(c)


GraphArea()

In [1]: import graphviz
   ...: 
   ...: class GraphArea(graphviz.Digraph):
   ...:     def __init__(self,
   ...:                  name='graph',
   ...:                  format='svg',
   ...:                  graph_attr={'rankdir': 'LR'},
   ...:                  node_attr={'shape': 'box'},
   ...:                  **kwargs):
   ...:         super().__init__(name=name,
   ...:                          format=format,
   ...:                          graph_attr=graph_attr,
   ...:                          node_attr=node_attr,
   ...:                          **kwargs)
   ...:                          
   ...:         
   ...: 
   ...: g = GraphArea()
   ...: with g.subgraph(name="cluster_0") as s:
   ...:     s.node('spam')
   ...: print(g)
digraph "graph" {
	graph [rankdir=LR]
	node [shape=box]
	subgraph cluster_0 {
		spam
	}
}

import functools

GraphArea = functools.partial(graphviz.Digraph,
                              name='graph',
                              format='svg',
                              graph_attr={'rankdir': 'LR'},
                              node_attr={'shape': 'box'})