My first scraper: Scrape zipatlas.com for population statistics per zipcode

pop_dens.py

def get_IA_pop_dens_ZIP():
    #scrapes table from http://zipatlas.com/us/ia/zip-code-comparison/population-density.htm 
    #and http://zipatlas.com/us/ia/zip-code-comparison/population-density.?.htm
    url_base = "http://zipatlas.com/us/ia/zip-code-comparison/"
    page1 = "population-density."
    pnum = [i for i in range(1,11)]
    htm = "htm"
    tables_pages =[]
    for page in pnum:
        if page==1:
            url = url_base + page1+ htm
        else:
            url = url_base + page1 + str(page) + "." + htm
        r = requests.get(url)
        soup = BeautifulSoup(r.text)
        tables = soup.find_all('table', {'rules': 'all'})
        tables_pages.append([[c.string for c in row.findAll("td")] for row in tables[0].findAll('tr')])
    return tables_pages