I was trying the following script, not to solve the problem but to try something out, and it appears to be accepted as a correct answer for the entire problem!
It clearly does not solve the problem. You can test remove_duplicates([3,4,3,4]) to see what I mean.
Does anyone know if this happens regularly? I am afraid that other problems for which I received a correct answer were not realy correctly solved.
def remove_duplicates(x): new_list = x return new_list print remove_duplicates