Unable to use functions from custom imported module

edit

Hi there, I'm a novice experimenting on making and using custom modules (python) having functions that is required for my rosnode. I can do the same in normal python, but I am struggling with the import. After I added the python script in CMakeLists.xml as executable script(python) , import didn't show error. Edited CMakeLists.xml :

## Mark executable scripts (Python etc.) for installation
## in contrast to setup.py, you can choose the destination
   catkin_install_python(PROGRAMS
    src/cmdvel_adapterv1.0
    src/server.py
    DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
  )

But now, when I try to use any function of server.py from cmdvel_adapterv1.0 :

#!/usr/bin/env python3
import server
import rospy
from std_msgs.msg import String


def callback(data):

    ---------


def function():

    port = 8081
    s = server.init_server(port)
   ----
    sub = rospy.Subscriber('cmdvel_socket_stream', String, callback)
    rospy.spin()



if __name__ == '__main__':

    try:
        rospy.init_node('cmdvel_adapter_v1_0')
        function()

    except rospy.ROSInterruptException:
        pass

in my rosnode, I get error -

    s = server.init_server(port)
AttributeError: module 'server' has no attribute 'init_server'

This is the Server.py module :-

import os
import socket

def dow():
    print("its accessing")


def get_ip():

    ip = socket.gethostname()
    return ip


def init_server(port):

    host = get_ip()
    server = socket.socket()
    server.bind((host,port))
    print('binded to ' + str(host) +':' + str(port))
    return server

What am I doing wrong here? This method worked outside ros, why not in ros. Help me.

Thanks in advance Paul Pavish