for num in numbers:
The way you are going about it is kinda wonky.
Let's start with the baisics.
What is the problem?
Problem: Remove all odd numbers!
Ok next how do we do that?
if number % 2 == 0: print(even)
Ok so we can find our even numbers good. Now we need to collect only the even numbers.
even_numbers =  for number in numbers: if number % 2 == 0: even_numbers.append(number)
When you use the method remove it will remove the first entry that it finds not all of them.
So instead of removing entries lets just build a list of the items that meet our quilifications.
list_numbers = [1, 2, 3, 4, 5, 6] def purify(number_list): return_list =  for number in number_list: if number % 2 == 0: return_list.append(number) return return_list
It is harder to remove something then it is to make a new list with what you want.
Thank you so much for help me out!
You can also do something like this:
def purify(l): for i in l[:]: # l[:] will create a copy of list you are looping through if i % 2 != 0: l.remove(i) return l