AttributeError while running ssh (from windows) paramiko need help

[darshak bavishi]

Hi Experts ,

while i am running following demo ssh script of paramiko -->

import base64
import getpass
import os
import socket
import sys
import traceback
 
import paramiko
import interactive
 
 
# setup logging
paramiko.util.log_to_file('demo_simple.log')
 
# get hostname
username = ''
if len(sys.argv) > 1:
    hostname = sys.argv[1]
    if hostname.find('@') >= 0:
        username, hostname = hostname.split('@')
else:
    hostname = raw_input('Hostname: ')
if len(hostname) == 0:
    print '*** Hostname required.'
    sys.exit(1)
port = 22
if hostname.find(':') >= 0:
    hostname, portstr = hostname.split(':')
    port = int(portstr)
 
 
# get username
if username == '':
    default_username = getpass.getuser()
    username = raw_input('Username [%s]: ' % default_username)
    if len(username) == 0:
        username = default_username
password = getpass.getpass('Password for %s@%s: ' % (username, hostname))
 
 
# get host key, if we know one
hostkeytype = None
hostkey = None
try:
    host_keys = paramiko.util.load_host_keys(os.path.expanduser('~/.ssh/known_hosts'))
except IOError:
    try:
        # try ~/ssh/ too, because windows can't have a folder named ~/.ssh/
        host_keys = paramiko.util.load_host_keys(os.path.expanduser('~/ssh/known_hosts'))
    except IOError:
        print '*** Unable to open host keys file'
        host_keys = {}
 
if host_keys.has_key(hostname):
    hostkeytype = host_keys[hostname].keys()[0]
    hostkey = host_keys[hostname][hostkeytype]
    print 'Using host key of type %s' % hostkeytype
 
 
# now, connect and use paramiko Transport to negotiate SSH2 across the connection
try:
    t = paramiko.Transport((hostname, port))
    t.connect(username=username, password=password, hostkey=hostkey)
    chan = t.open_session()
    chan.get_pty()
    chan.invoke_shell()
    print '*** Here we go!'
    print
    interactive.interactive_shell(chan)
    chan.close()
    t.close()
 
except Exception, e:
    print '*** Caught exception: %s: %s' % (e.__class__, e)
    traceback.print_exc()
    try:
        t.close()
    except:
        pass
    sys.exit(1)

It gives error as follows :

Warning (from warnings module):
File "C:\Python26\lib\site-packages\Crypto\Hash\SHA.py", line 6
from sha import *
DeprecationWarning: the sha module is deprecated; use the hashlib module instead

Warning (from warnings module):
File "C:\Python26\lib\site-packages\Crypto\Hash\MD5.py", line 6
from md5 import *
DeprecationWarning: the md5 module is deprecated; use hashlib instead
Hostname: 10.135.15.41
Username [admin]: root

Warning (from warnings module):
File "C:\Python26\lib\getpass.py", line 88
return fallback_getpass(prompt, stream)
GetPassWarning: Can not control echo on the terminal.
Warning: Password input may be echoed.
Password for root@10.135.15.41: alcatel
*** Unable to open host keys file
*** Here we go!

Line-buffered terminal emulation. Press F6 or ^Z to send EOF.



Last login: Mon Dec 13 19:38:31 2010 from 10.135.19.50


*** Caught exception: <type 'exceptions.AttributeError'>: read
Traceback (most recent call last):
File "C:\Python26\paramiko-1.7.4\demos\demo_simple.py", line 90, in <module>
interactive.interactive_shell(chan)
File "C:\Python26\paramiko-1.7.4\demos\interactive.py", line 36, in interactive_shell
windows_shell(chan)
File "C:\Python26\paramiko-1.7.4\demos\interactive.py", line 91, in windows_shell
d = sys.stdin.read(1)
File "C:\Python26\lib\idlelib\rpc.py", line 560, in __getattr__
raise AttributeError, name
AttributeError: read


*** EOF ***

Traceback (most recent call last):
File "C:\Python26\paramiko-1.7.4\demos\demo_simple.py", line 101, in <module>
sys.exit(1)
SystemExit: 1

can you tell me what is use of Hostkey and how to overcome this issue?!