Python: Using a List of Lists in a Function

n = [[1, 2, 3], [4, 5, 6, 7, 8, 9]]
def flatten(lists):
results = []
for lst in lists:
    for numbers in lst:
results.append(numbers)
return results
print flatten(n)
WordPress keeps trying to remove my indentations, which is a pretty huge problem. Lines 3 and 4 should be more indented than 1 an 2. Line 5 has an additional indentation and line 6 has one more . Line 7 is less indented by 2 and line 8 returns to the original level of indendation.