Python 2 code to extract real estate listings from zillow.com

zillow.py

from lxml import html
import requests
import unicodecsv as csv
from exceptions import ValueError
import argparse

def parse(zipcode,filter=None):

	if filter=="newest":
		url = "https://www.zillow.com/homes/for_sale/{0}/0_singlestory/days_sort".format(zipcode)
	elif filter == "cheapest":
		url = "https://www.zillow.com/homes/for_sale/{0}/0_singlestory/pricea_sort/".format(zipcode)
	else:
		url = "https://www.zillow.com/homes/for_sale/{0}_rb/?fromHomePage=true&shouldFireSellPageImplicitClaimGA=false&fromHomePageTab=buy".format(zipcode)
	
	for i in range(5):
		try:
			headers= {
						'accept':'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
						'accept-encoding':'gzip, deflate, sdch, br',
						'accept-language':'en-GB,en;q=0.8,en-US;q=0.6,ml;q=0.4',
						'cache-control':'max-age=0',
						'upgrade-insecure-requests':'1',
						'user-agent':'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36'
			}
			response = requests.get(url, headers=headers, verify=False)
			parser = html.fromstring(response.text)
			search_results = parser.xpath("//div[@id='search-results']//article")
			properties_list = []
			
			for properties in search_results:
				raw_address = properties.xpath(".//span[@itemprop='address']//span[@itemprop='streetAddress']//text()")
				raw_city = properties.xpath(".//span[@itemprop='address']//span[@itemprop='addressLocality']//text()")
				raw_state= properties.xpath(".//span[@itemprop='address']//span[@itemprop='addressRegion']//text()")
				raw_postal_code= properties.xpath(".//span[@itemprop='address']//span[@itemprop='postalCode']//text()")
				raw_price = properties.xpath(".//span[@class='zsg-photo-card-price']//text()")
				raw_info = properties.xpath(".//span[@class='zsg-photo-card-info']//text()")
				raw_broker_name = properties.xpath(".//span[@class='zsg-photo-card-broker-name']//text()")
				url = properties.xpath(".//a[contains(@class,'overlay-link')]/@href")
				raw_title = properties.xpath(".//h4//text()")
				
				address = ' '.join(' '.join(raw_address).split()) if raw_address else None
				city = ''.join(raw_city).strip() if raw_city else None
				state = ''.join(raw_state).strip() if raw_state else None
				postal_code = ''.join(raw_postal_code).strip() if raw_postal_code else None
				price = ''.join(raw_price).strip() if raw_price else None
				info = ' '.join(' '.join(raw_info).split()).replace(u"\xb7",',')
				broker = ''.join(raw_broker_name).strip() if raw_broker_name else None
				title = ''.join(raw_title) if raw_title else None
				property_url = "https://www.zillow.com"+url[0] if url else None 
				is_forsale = properties.xpath('.//span[@class="zsg-icon-for-sale"]')
				properties = {
								'address':address,
								'city':city,
								'state':state,
								'postal_code':postal_code,
								'price':price,
								'facts and features':info,
								'real estate provider':broker,
								'url':property_url,
								'title':title
				}
				if is_forsale:
					properties_list.append(properties)
			return properties_list
		except:
			print "Failed to process the page",url

if __name__=="__main__":
	argparser = argparse.ArgumentParser(formatter_class=argparse.RawTextHelpFormatter)
	argparser.add_argument('zipcode',help = '')
	sortorder_help = """
    available sort orders are :
    newest : Latest property details,
    cheapest : Properties with cheapest price
    """
	argparser.add_argument('sort',nargs='?',help = sortorder_help,default ='Homes For You')
	args = argparser.parse_args()
	zipcode = args.zipcode
	sort = args.sort
	print "Fetching data for %s"%(zipcode)
	scraped_data = parse(zipcode,sort)
	print "Writing data to output file"
	
	with open("properties-%s.csv"%(zipcode),'w')as csvfile:
		fieldnames = ['title','address','city','state','postal_code','price','facts and features','real estate provider','url']
		writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
		writer.writeheader()
		for row in  scraped_data:
			writer.writerow(row)

I can run it with no errors, but returns an empty csv file other than headers for any zip code / sorting combination. Output shown below:

C:\py>python zillow.py 77354 newest
Fetching data for 77354
C:\Python27\lib\site-packages\urllib3\connectionpool.py:858: InsecureRequestWarning: Unverified HTTPS request is being made. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#ssl-warnings InsecureRequestWarning)
C:\Python27\lib\site-packages\urllib3\connectionpool.py:858: InsecureRequestWarning: Unverified HTTPS request is being made. Adding certificate verification is strongly advised. See: https://urllib3.readthedocs.io/en/latest/advanced-usage.html#ssl-warnings InsecureRequestWarning)
Writing data to output file