如何从python中的图形中删除边

How do I delete an edge from a graph in Python

我在读ThinkComplexity的书，我对Python不熟悉，所以我有以下代码：

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class Graph(dict):
def __init__(self, vs=[], es=[]):
"""
:param vs: list of vertices/nodes in the graph
:param es: list of edges/connection for the nodes
:return: Object graph
"""

for v in vs:
self.add_vertex(v) #also node
for e in es:
self.add_edge(e) #arc/edge/line

def add_vertex(self, v):
"""
:param v: Add the node/vertex to the graph
:return: Nothing just add
"""
self[v] = {}

def add_edge(self, e):
"""
:param e: Add arc/edge/line to the graph here is in both directions as it is undirected graph, if there is a arc already replace it
:return: Nothing just add
"""
v, w = e
self[v][w] = e
self[w][v] = e

def get_edge(self, v1, v2):
try:
if self != None:
if self[v1][v2] == self[v2][v1]:
print 'got it'
return True

except:
return None

def remove_edge(self, e, e2):
try:
if self != None:
del self[e][e2]
del self[e2][e]
print 'deleted
', e[0], e[1]
return True

except:
return None

def vertices(self): #get the list of nodes
nodes = []
for node in self.keys():
nodes.append(node.label)
print nodes, '
'
return nodes

def edges(self):
list_edges = []
count = 0
for node in self:
for edges in self[node]:
count += 1
print self[node].values(), count
list_edges.append(self[node].values())

return list_edges

def out_vertices(self, v): #nodes connected to this node
connected = []
for node in v.keys():
connected.append(node)
print node, 'this node is connected to', v.keys()

return connected

def out_edges(self, v):
list_out_edges = []
for ed in v.values():
print ed, 'edges from to'
list_out_edges.append(ed)

return list_out_edges

class Vertex(object): #nodes fro the graph
def __init__(self, label=''):
self.label = label

def __repr__(self):
return 'Vertex/Node(%s)' % repr(self.label)

__str__= __repr__

class Edge(tuple):
def __new__(cls, e1, e2):
return tuple.__new__(cls, (e1, e2))

def __repr__(self):
return 'Edge(%s---%s) <-undirected' % (repr(self[0]), repr(self[1]))

__str__ = __repr__

在第24章。编写一个名为remove_edge的方法，该方法获取一条边并从图形中删除对它的所有引用。

我已经完成了get-edge()代码，但是不删除，我不知道该怎么做，有什么帮助吗？？这将是Bayes网络的一个起点，所以我想了解一下Python和图形。谢谢