Python 3 telnetlib router reboot

I am trying to write a python script to reboot my router.

I can do this just fine with normal telnet, however, in the python code, for some reason, unless I add tn.read_all() to the bottom of the code, reboot operation does not execute. Here is the current working code:

import sys
import telnetlib
import time

HOST = "192.168.0.1"
password = "12345678"

try:
    with telnetlib.Telnet(HOST,23,timeout=10) as tn:
        print(tn.read_until(b'password:', 5))
        tn.write((password + '\r\n').encode('ascii'))
        print(tn.read_until(b'(conf)#', 5))
        tn.write(('dev reboot' + '\r\n').encode('ascii'))
        time.sleep(1)
        print(tn.read_all().decode('ascii'))
        
except EOFError:
    print("Unexpected response from router")
except ConnectionRefusedError:
    print("Connection refused by router. Telnet enabled?")
except:
    print("Error")

The normal output for the telnet operation is:

--------------------------------------------------------------------------------
Welcome To Use TP-Link COMMAND-LINE Interface Model.
--------------------------------------------------------------------------------
TP-Link(conf)#dev reboot
[ oal_sys_reboot ] 489:  now sleep for 2 secs

TP-Link(conf)#killall: pppd: no process killed

Keeping read_all() makes the operation timeout with printing "error" defined in the exceptions. I want to keep this clean and simple. How can I achieve this?

Apparently, the delay was not enough and the connection was closing quickly. Adding read_all was keeping the connection open so commands executed when it was added. Solution was to increase the delay from 1s to 5s.

import sys
import telnetlib
import time

HOST = "192.168.0.1"
password = "12345678"
port = 23

try:
    print('Opening Telnet Connection to Router.')
    with telnetlib.Telnet(HOST,port,timeout=10) as tn:
        tn.read_until(b'password:', 10)
        print('Sending password to Router.')
        tn.write((password + '\r\n').encode('ascii'))
        time.sleep(1)
        tn.read_until(b'(conf)#', 10)
        print('Rebooting the Router!!!')
        tn.write(('dev reboot' + '\r\n').encode('ascii'))
        time.sleep(5)
        
except EOFError:
    print("Unexpected response from router")
except ConnectionRefusedError:
    print("Connection refused by router. Telnet enabled?")
except:
    print("Error")