Improved Python 3 compatibility.

Added Exception type at the urllib import statement.
raw_input() was replaced by input() in Python 3, so NameError exception will be raised in Python 3 and input() would be used instead.

udemy-dl.py

@@ -9,10 +9,11 @@
 import os
 import json
 from bs4 import BeautifulSoup
+
 try:
-    from urllib import urlretrieve
-except:
-    from urllib.request import urlretrieve
+    from urllib import urlretrieve  # Python 2
+except ImportError:
+    from urllib.request import urlretrieve  # Python 3
 
 
 class Session:
@@ -159,12 +160,16 @@ def main():
     link = args['link']
 
     if not username:
-        print('Username/Email:'),
-        username = raw_input()
+        try:
+            username = raw_input("Username/Email: ")  # Python 2
+        except NameError:
+            username = input("Username/Email: ")  # Python 3
+
     if not password:
         password = getpass.getpass(prompt='Password: ')
 
     udemy_dl(username, password, link)
 
+
 if __name__ == '__main__':
     main()