The following code failed with an error
Traceback (most recent call last):
File "python", line 12, in
File "python", line 7, in flatten
TypeError: object of type 'int' has no len()
n = [[1, 2, 3], [4, 5, 6, 7, 8, 9]]
Add your function here
results = 
for numbers in range(len(lists)): for number in range(len(numbers)): results.append(number) return results
When I changed the code without using range(), it worked.
Why does it take "numbers" to be an integer, rather than a list?