python2.7写的图形密码生成器

#coding:utf8
import random,wx
def password(event):
    a = [chr(i) for i in range(97,123)]
    b = [chr(i) for i in range(65,91)]
    c = ['0','1','2','3','4','5','6','7','8','9']
    d = ['!','@','#','$','%','^','&','*','(',')','=','_','+','/','?']

    set1 = a + b + c + d
    set2 = a + b + c
    num = int(length.GetValue())
    if switch.GetValue() == 0:
        passwd = ''.join(random.sample(set1,num))
        contents.SetValue(passwd)
    else:
        passwd = ''.join(random.sample(set2,num))
        contents.SetValue(passwd)
app = wx.App()
win = wx.Frame(None,-1,title=u'密码生成器',size=(480,200))
bkg = wx.Panel(win,-1)

# tt = wx.StaticText(bkg,-1,u'屏蔽输入字符')
# delete = wx.TextCtrl(bkg,-1)

right = wx.Button(bkg,-1,label=u'确定生成')
right.Bind(wx.EVT_BUTTON,password)

stxt = wx.StaticText(bkg,-1,u'请输入你的密码长度位数！' )
length = wx.TextCtrl(bkg,-1,size=(50,27))
switch = wx.CheckBox(bkg, -1,u'关闭特殊字符',(150, 20))

sobx = wx.BoxSizer()
sobx.Add(stxt,proportion=0,flag=wx.ALL,border=5)
sobx.Add(length,proportion=1,border=5)
sobx.Add(switch,proportion=0,flag=wx.ALL | wx.ALIGN_RIGHT,border=5)

sobx.Add(right,proportion=0,flag=wx.EXPAND,border=5)

contents = wx.TextCtrl(bkg,-1)
cobx = wx.BoxSizer()
cobx.Add(contents,proportion=1,flag=wx.EXPAND,border=5)

dobx = wx.BoxSizer()

# dobx.Add(delete,proportion=1,flag=wx.ALL,border=5)

robx = wx.BoxSizer(wx.VERTICAL)
robx.Add(cobx,proportion=1,flag=wx.EXPAND | wx.ALL,border=5)
robx.Add(sobx,proportion=0,flag=wx.ALL,border=5)
# robx.Add(dobx,proportion=0,flag=wx.EXPAND,border=5)

bkg.SetSizer(robx)

win.Show()
app.MainLoop()