New to Python, can you please help with a question??

[kylie991]

Hi I am new to Python. I am stuck on this question..... I know it is only simple but it just will not work for me and I have spent hours looking at the screen.. :(

below is some code. The first fuction is to simply return the average rating of the video and a count.... I thought I did this right as when I create a separate shell that links to the database it provides the average and the count. (number of ratings added to the database) But when I run the the test script it comes up with an error message saying

line 145, in test_average_rating
(avg, count) = util.average_rating(vid)
TypeError: 'NoneType' object is not iterable

What does this mean???

below is my code for that function and also another one.... I'm only very new to this so I am getting so frustrated with myself and am finding the university is not helping me much at all...

def average_rating(video_id):
    """Return the average rating for this video and
    the number of votes as a tuple (avg, count)"""
 
    con = connect()
    cur = con.cursor()
 
    average = cur.execute("select AVG(rating), count(rating) from ratings")
    for ratings in average:
        print ratings
 
def add_rating(video_id, email, rating, comment):
    """Add a rating for a given video and user email.
    If the video or user doesn't exist, or if the rating is
    outside of the range 1-5, raise an exception of
    type WebappError with a message that can be
    shown to the user.
    """
 
    con = connect()
    cur = conn.cursor()
 
    cur.execute("INSERT INTO ratings(video, email, rating, comment) VALUES ('?','?','?','?')")
    conn.commit()

[bvdet]

Add a print statement after you assign the cursor query to variable average. I think you will find that average is not an object you can iterate on.

>>> av = 1
>>> for obj in av:
...     print obj
...     
Traceback (most recent call last):
  File "<interactive input>", line 1, in ?
TypeError: iteration over non-sequence
>>> 

What fields are in the ratings table?