Cleanup python formatting for PEP 8

combine.py

@@ -2,42 +2,43 @@
 from os import sep
 from PyPDF2 import PdfFileMerger
 
+RENDER_DIR = "render"
+DOWNLOAD_EXTRA_FLAG = True
+SITE_MAIN = "https://projecteuler.net/"
 
 
-render_dir = "render"
-download_extra_flag = True
-
 def download_extra(url):
-    '''Tries to find a .txt attachment or .gif and download it to render_dir.'''
-    # TODO async request
+    """Finds if available a .txt attachment or animated .gif and downloads it
+    to RENDER_DIR
+    """
+    # Not async for now to keep rate of requests low
     from bs4 import BeautifulSoup
     import requests
     from os.path import basename
     from PIL import Image
     from io import BytesIO
 
-    site_main = "http://projecteuler.net/"
-
     print("Searching", url)
     content = requests.get(url).content
     soup = BeautifulSoup(content, "lxml")
     for a in soup.find_all('a', href=True):
-        if a["href"].endswith(".txt"):
-            print("Found", a["href"])
-            r = requests.get(site_main + a["href"])
-            with open(render_dir + sep + a.text, 'wb') as f:
+        href = a["href"]
+        if href.endswith(".txt"):
+            print("Found and writing", href)
+            r = requests.get(SITE_MAIN + href)
+            with open(RENDER_DIR + sep + a.text, 'wb') as f:
                 f.write(r.content)
 
     for img in soup.find_all("img"):
         img_src = img["src"]
         # Ignore spacer.gif (blank)
         if img_src.endswith(".gif") and "spacer" not in img_src:
             print("Found", img_src)
-            r = requests.get(site_main + img_src)
+            r = requests.get(SITE_MAIN + img_src)
             # Only write animated GIFs
             if Image.open(BytesIO(r.content)).is_animated:
                 print("Writing", img_src)
-                with open(render_dir + sep + basename(img_src), 'wb') as f:
+                with open(RENDER_DIR + sep + basename(img_src), 'wb') as f:
                     f.write(r.content) 
 
 
@@ -48,22 +49,20 @@ def main():
     merger = PdfFileMerger()
 
     for problem_id in range(problem_id_start, problem_id_end+1):
-        pdf_path = render_dir + sep + str(problem_id) + ".pdf"
+        pdf_path = RENDER_DIR + sep + str(problem_id) + ".pdf"
         merger.append(pdf_path)
 
-    merger.write(render_dir + sep + "problems.pdf")
+    merger.write(RENDER_DIR + sep + "problems.pdf")
     print("Merged PDFs")
 
-
-    if download_extra_flag:
+    if DOWNLOAD_EXTRA_FLAG:
         url_list = []
         for problem_id in range(problem_id_start, problem_id_end+1):
-            url_list.append("https://projecteuler.net/problem=" + str(problem_id))
+            url_list.append(SITE_MAIN + "problem=" + str(problem_id))
 
         for url in url_list:
             download_extra(url)
 
 
 if __name__ == "__main__":
     main()
-