Fails to execute function when called from different file in python

Have two files.

1 updatelib.py -- where function is defined. 2 test.py -- where I am calling function.

content of each file as follows:

CONTENT OF updatelib.py

import os, sys, re, time
import pexpect

def update(session):

    try:
        session.sendline("testapp")
        time.sleep(5)
        print "open test app"
        session.expect_exact("Enter command")
        time.sleep(5)
        session.sendline("1")
        time.sleep(5)
        session.expect_exact("success")
        print ("test is pass")
    except:
        print "Fail:("

CONTENT OF TEST.PY

import os, sys, re, time
import pexpect
import updatelib

updatelib.update(session)
time.sleep(120)
session.close()

QUESTION

It works perfectly fine when I call update(session) function within updatelib.py

But when I try to the call the same function from test.py, it prints "open test app" then goes into except and prints "Fail:("

Note: "testapp" is a utility that is available with 1-10 options

Any pointers to what am I missing here?