Trying to import podcasts with no artworkURL

main.py

@@ -38,7 +38,7 @@ class podcasts(db.Model):
     userID = db.Column(db.Integer)
     title = db.Column(db.Text)
     URL = db.Column(db.Text)
-    artworkURL = db.Column(db.Text)
+    artworkURL = db.Column(db.Text, default=None)
 
 
 @app.route('/', methods=['GET'])
@@ -132,7 +132,7 @@ def addFeed():
     if not parsed.feed.title:
         artwork = str(parsed.feed.image)
     else:
-        artwork = None
+        artwork = ''
 
 # checks to see if the podcast URL already exists for logged in user and skips it if it has already been imported.
 # if the show doesn't already exist for the logged in user it gets added