Cisco Device SSH with paramiko including thread

import paramiko
import time
import datetime
import re
import sys
import getpass
import time
from datetime import date
from datetime import datetime
import os
import socket
import threading

def get_filename_datetime():
    # Use current date & time to get a text file name.
        return str(datetime.now().strftime('%Y_%m_%d %H_%M_%S'))

# Get full path for writing.
fname = get_filename_datetime()

user = input("Enter your M-account username: ")
password = getpass.getpass("Enter your M-account Password: ")


def ssh_conn(HOST):
    try:
        ssh = paramiko.SSHClient()
        ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        ssh.connect(HOST, port=22, username=user, password=password, look_for_keys=False, timeout=8, banner_timeout=5)
        connection = ssh.invoke_shell()
        connection.send("show run | se vty\n")
        time.sleep(10)
        connection.send("configure terminal\n")
        connection.send("\n")
        connection.send("line vty 0 15\n")
        connection.send("transport input ssh\n")
        connection.send("exit\n")
        connection.send("do write memory\n")
        connection.send("\n" * 2)
        time.sleep(3)
        file_output = connection.recv(99999999).decode(encoding='utf-8')
        hostname = (re.search('(.+)#', file_output)).group().strip('#')
        print(file_output)
        outFile = open(hostname + "_" + HOST + ".txt", "w")
        outFile.writelines(file_output)
        outFile.close()
        ssh.close()
        print("*" * 20 + " " + "%s is done" % hostname + " " + "*" * 20)

    except paramiko.AuthenticationException:
        print("X" * 20 + " " + HOST + ' === Bad credentials ' + "X" * 20)
    except paramiko.SSHException:
        print("X" * 20 + " " + HOST + ' === Issues with ssh service ' + "X" * 20)
    except socket.error:
        print("X" * 20 + " " + HOST + ' === Device unreachable ' + "X" * 20)


def SSH_Thread():
    thread_instance = []
    ips = [i.strip() for i in open("switchlist.txt")] # creates a list from input file
    for HOST in ips:
        trd = threading.Thread(target=ssh_conn, args=(HOST.strip("\n"),))
        trd.start()
        thread_instance.append(trd)

    for trd in thread_instance:
        trd.join()

if __name__ == '__main__':
    SSH_Thread()