diff --git a/VC-Downloader.py b/VC-Downloader.py
index cdef6fc..c227718 100644
--- a/VC-Downloader.py
+++ b/VC-Downloader.py
@@ -1,3 +1,18 @@
+########################################################################
+#                                                                      #
+# This program is free software: you can redistribute it and/or modify #
+# it under the terms of the GNU General Public License as published by #
+# the Free Software Foundation, version 3.                             #
+#                                                                      #
+# This program is distributed in the hope that it will be useful, but  #
+# WITHOUT ANY WARRANTY; without even the implied warranty of           #
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU     #
+# General Public License for more details.                             #
+#                                                                      #
+# You should have received a copy of the GNU General Public License    #
+# *along with this program. If not, see <http://www.gnu.org/licenses/>.#
+########################################################################
+
 import os.path
 
 from bs4 import BeautifulSoup
@@ -13,57 +28,75 @@ def downloader(input):
     link = input[1]
     s = input[2]
     r = s.get(link, stream=True)
-    total_size_in_bytes = int(r.headers.get('content-length'))
+    total_size_in_bytes = int(r.headers.get("content-length"))
     block_size = 1024
 
     if os.path.exists(filename) and os.path.getsize(filename) == total_size_in_bytes:
-        print(f'{filename} has already been downloaded!')
+        print(f"{filename} has already been downloaded!")
     else:
-        progress_bar = tqdm(total=total_size_in_bytes, unit='iB', unit_scale=True,desc=filename)
-        with open(filename, 'wb') as file:
+        progress_bar = tqdm(
+            total=total_size_in_bytes, unit="iB", unit_scale=True, desc=filename
+        )
+        with open(filename, "wb") as file:
             for data in r.iter_content(block_size):
                 progress_bar.update(len(data))
                 file.write(data)
         progress_bar.close()
 
 
-if __name__ =='__main__':
-    print("""This is a simple App for downloading mp4 from vc.kntu.ac.ir.
-    Written by: Hoorad Farrokh and Mojtaba Farrokh""")
+if __name__ == "__main__":
+    print(
+        """This is a simple App for downloading mp4 from vc.kntu.ac.ir.
+    Written by: Hoorad Farrokh and Mojtaba Farrokh"""
+    )
     # Use 'with' to ensure the session context is closed after use.
     Video_url = input("Enter the url of the page that contains videos link:\n")
-    login = input('Enter username:')
-    passwd = pwinput.pwinput("Enter password:",mask='*')
-    if sys.platform == 'win32':
+    login = input("Enter username:")
+    passwd = pwinput.pwinput("Enter password:", mask="*")
+    if sys.platform == "win32":
         import certifi_win32
 
-        os.environ['REQUESTS_CA_BUNDLE'] = certifi_win32.wincerts.where()
+        os.environ["REQUESTS_CA_BUNDLE"] = certifi_win32.wincerts.where()
         certifi_win32.generate_pem()
 
     with requests.Session() as s:
-        r = s.get(Video_url.split('mod')[0]+"login/index.php")
+        r = s.get(Video_url.split("mod")[0] + "login/index.php")
         cookie = r.cookies.get_dict()
         pattern = '<input type="hidden" name="logintoken" value="\w{32}">'
         token = re.findall(pattern, r.text)
         # print(token)
         token = re.findall("\w{32}", token[0])
-        payload = {'username': login, 'password': passwd, 'anchor': '', 'logintoken': token[0]}
+        payload = {
+            "username": login,
+            "password": passwd,
+            "anchor": "",
+            "logintoken": token[0],
+        }
 
-        p = s.post(Video_url.split('mod')[0]+"login/index.php", cookies=r.cookies, data=payload)
+        p = s.post(
+            Video_url.split("mod")[0] + "login/index.php",
+            cookies=r.cookies,
+            data=payload,
+        )
 
         # print the html returned or something more intelligent to see if it's a successful login page.
 
         # create response object
-        r = s.get(Video_url,cookies=p.cookies)
+        r = s.get(Video_url, cookies=p.cookies)
         # create beautiful-soup object
-        soup = BeautifulSoup(r.content, 'html5lib')
+        soup = BeautifulSoup(r.content, "html5lib")
 
         # find all links on web-page
-        links = soup.findAll('a')
+        links = soup.findAll("a")
         # filter the link ending with .mp4
-        video_links = [Video_url.split('view')[0] + link['href'] for link in links if 'mp4' in link['href']]
+        video_links = [
+            Video_url.split("view")[0] + link["href"]
+            for link in links
+            if "mp4" in link["href"]
+        ]
         temp = []
         for i in range(len(video_links)):
-            temp.append((f'session {i+1}.mp4',video_links[i],s))
-        print(f'Number of sessions to be downloaded is {len(temp)}.')
-        for tt in temp: downloader(tt)
\ No newline at end of file
+            temp.append((f"session {i+1}.mp4", video_links[i], s))
+        print(f"Number of sessions to be downloaded is {len(temp)}.")
+        for tt in temp:
+            downloader(tt)