the python code below has a problem when i run the code. what wrong with this line in code: ptime += 1

# We will need the following modules for system and time information

import sys, time

from socket import *

# Get the server hostname and port as command line arguments

argv = sys.argv

host = argv[1]

port = argv[2]

# Set initial timeout value

timeout = 2 # number of seconds before timeout

# Create UDP client socket

# Note the use of SOCK_DGRAM for UDP datagram packet

clientsocket = socket(AF_INET, SOCK_DGRAM)

# Set socket timeout

clientsocket.settimeout(timeout)

# Command line argument is a string, change the port into integer

port = int(port)

# Sequence number of the ping message

ptime = 0

# Ping for 10 times

while ptime < 10:

ptime += 1

# Format the message to be sent

data = "Pinging: " + str(ptime) + ", " + time.asctime()

# Display the message

print ("Ping Message from Client: " + data)

try:

# Sent time

RTTb = time.time()

# Send the UDP packet with the ping message

clientsocket.sendto(data,(host, port))

# Receive the server response

message, address = clientsocket.recvfrom(1024)

# Received time

RTTa = time.time()

# Display the server response as an output

print ("Reply from " + address[0] + ": " + message)

# Round trip time is the difference between sent and received time

print ("RTT: " + str(RTTa - RTTb))

except:

# Server does not response

# Assume the packet is lost

print ("Request timed out. ")

continue

# Close the client socket

clientsocket.close()