Refactor index_get() with early returns.

undercover/routes.py

@@ -109,16 +109,21 @@ def logout():
 @writing_blueprint.route('/', methods=['GET'])
 def index_get():
     email_address = session.get('username')
+    if not email_address:
+        return render_index()
+
     form = CLForm()
-    if email_address:
     user = db.get_user(email_address)
     letters = db.get_user_letters(user.id)
-        if len(letters) > 0:
+    if len(letters) == 0:
+        return render_index()
+
     letter_names = [(i + 1, letter.title) for i, letter in enumerate(letters)]
     form.letterName.choices = letter_names
 
     form.letterName.data = 1
     selected_letter = request.args.get('letter_name')
+
     if selected_letter:
         for i, letter in enumerate(letters):
             if letter.title == selected_letter: