AttributeError: 'NoneType' object has no attribute error

[vk7]

I am writing a python script for scrapping weather of different city from weather-forecast website. I got an AttributeError in my code and i am unable to gets the cause of error.

Here is my code:

import urllib.request, urllib.parse, urllib.error
import ssl
import re

# Ignore SSL certificate errors
ctx = ssl.create_default_context()
ctx.check_hostname = False
ctx.verify_mode = ssl.CERT_NONE

condition = 1
braces = '<'

while(condition):
    end = 0
    start = 0
    city = input('enter city: ')
    url = "http://www.weather-forecast.com/locations/" + city + "/forecasts/latest"
    rawData = urllib.request.urlopen(url, context=ctx).read()
    data = rawData.decode()
    string = re.search('1 &ndash; 3 Day Weather Forecast Summary:</b><span class="read-more-small"><span class="read-more-content"><span class="phrase">', data)
    start = string.end()

    i = 0
    for i in range(start,start+500):
        if data[i] == braces:
            end = i
            break

    weather = data[start:end]
    final = weather.replace("&deg;C"," °C")
    print(final)
    print("")

This is an error occured:

Error:
enter city: Mumbai
Traceback (most recent call last):
  File "C:\Users\VISHAL\Desktop\wf\weather.py", line 21, in <module>
    start = string.end()
AttributeError: 'NoneType' object has no attribute 'end'