Using a list of lists in a function


I am experiencing some difficulty with this exercise requiring a function to flatten a list of lists.

My code:

def flatten(lists):
    results = []
    for numbers in lists:
        for i in numbers:
    return results

generates the following errors which I have been unable to debug

Any suggestions how to resolve this much appreciated.



what does i contain? not indexes, but actually items from the list so you can just append i to results.



Thank you for the speedy response.



Well, the response has to be swift, this is the last week before the course closes and you have to move to the new course