Фильтр скачанных pdf

import urllib.request
scn_amount = 3
page_amount = 10
for scn in range (0, scn_amount + 1):
    for current_page in range (0, page_amount + 1):
        current_page_formated = (4 - len(str(current_page))) * '0' + str(current_page)
        scn_formatted = (4 - len(str(scn))) * '0' + str(scn)
        url = "http://www.studentlibrary.ru/cgi-bin/mb4x?usr_data=gd-image(doc,ISBN9785804105694-SCN"+scn_formatted+","+current_page_formated+".pdf,-1,,00000000,5001343be31662a586a453csnackes)&hide_Cookie=yes"
        urllib.request.urlretrieve(url, "глава "+str(scn)+" страница "+str(current_page)+".pdf")

>>> import urllib.request
>>> import urllib.parse
>>> params = urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})
>>> url = "http://www.musi-cal.com/cgi-bin/query?%s" % params
>>> with urllib.request.urlopen(url) as f:
...     print(f.read().decode('utf-8'))

import requests
scn_amount = 3
page_amount = 10
for scn in range (0, scn_amount + 1):
    for current_page in range (0, page_amount + 1):
        current_page_formated = (4 - len(str(current_page))) * '0' + str(current_page)
        scn_formatted = (4 - len(str(scn))) * '0' + str(scn)
        url = "http://www.studentlibrary.ru/cgi-bin/mb4x?usr_data=gd-image(doc,ISBN9785804105694-SCN"+scn_formatted+","+current_page_formated+".pdf,-1,,00000000,5001343be31662a586a453csnackes)&hide_Cookie=yes"
        r = requests.get(url)
        with open("глава "+str(scn)+" страница "+str(current_page)+".pdf", "wb") as code:
            code.write(r.content)

import requests
 
scn_amount = 3
page_amount = 10
 
session = requests.Session()
 
for scn in range (scn_amount + 1):
    for page in range (page_amount + 1):
        p = "{:04d}".format(page)
        s = "{:04d}".format(scn)
 
        print("checking", p, s)
 
        url_template = "http://www.studentlibrary.ru/cgi-bin/mb4x?usr_data=gd-image(doc,ISBN9785804105694-SCN{},{}.pdf,-1,,00000000,5001343be31662a586a453csnackes)&hide_Cookie=yes"
        url = url_template.format(s, p)
        
        resp = session.get(url)
        if resp.status_code == 200:
            content_type = resp.headers.get('Content-Type', '')
 
            if 'pdf' in content_type:
                fn = "глава {} страница {}.pdf".format(s, p)
                print('writing', fn)
                with open(fn, 'wb') as data:
                    data.write(resp.content)