python-ldap wrong auth. after server down

[mete b. <met...@gm...>]

Hi all,
i'm trying to connect ldap into python. when i give it to true username and
password, nothing going wrong...But i try to wrong password ,the server
shutdown...How can i pass that.

ps:
ldap_server=ldap.open('localhost')
ldap_server.protocol_version = ldap.VERSION3
try:
    ldap_server.simple_bind_s(word,password)
    return 'bind yapıldı'
    ldap_server.unbind()
except ldap.LDAPError, e:
    return e