sample code to explain the fail design of default argument support in python

sample.py

class Member:
    def __init__(self,name='',group=''):
        self.name = name
        self.group = group

class Team:
    def __init__(self, names):
        self.members = [Member(n,str(hash(self))) for n in names]
    def join_us(self,member=Member()):
        self.members.append(member)
        member.group = str(hash(self))
        return member
    def print_members(self):
        for n in self.members:
            print n.name+"\t"+n.group
        
dev_team = Team(['john'])
test_team = Team(['smith','tom'])

tom = test_team.members[1]
dev_team.join_us(tom)

new_guy = dev_team.join_us()
new_guy.name = 'xman'

another_new_guy = dev_team.join_us()
another_new_guy.name = 'jim'

dev_team.print_members()