what can i do diffrently to slim down my python code?

class Edge(object):

def __init__(self, u, v, w):

self.source = u

self.sink = v

self.capacity = w

def __repr__(self):

return "%s->%s:%s" % (self.source, self.sink, self.capacity)

class FlowNetwork(object):

def __init__(self):

self.adj = {}

self.flow = {}

def add_vertex(self, vertex):

self.adj[vertex] = []

def get_edges(self, v):

return self.adj[v]

def add_edge(self, u, v, w=0):

if u == v:

raise ValueError("u == v")

edge = Edge(u,v,w)

redge = Edge(v,u,0)

edge.redge = redge

redge.redge = edge

self.adj[u].append(edge)

self.adj[v].append(redge)

self.flow[edge] = 0

self.flow[redge] = 0

def find_path(self, source, sink, path):

if source == sink:

return path

for edge in self.get_edges(source):

residual = edge.capacity - self.flow[edge]

if residual > 0 and not (edge,residual) in path:

result = self.find_path( edge.sink, sink, path + [(edge,residual)] )

if result != None:

return result

def max_flow(self, source, sink):

path = self.find_path(source, sink, [])

while path != None:

flow = min(res for edge,res in path)

for edge,res in path:

self.flow[edge] += flow

self.flow[edge.redge] -= flow

path = self.find_path(source, sink, [])

return sum(self.flow[edge] for edge in self.get_edges(source))