I got stucked in this exercise and I don't know why.
I executed that code, using my installed python interpreter and received correct results.
Here on codecademy the following error return:
"Oops, try again. Your function fails on purify([4, 5, 5, 4]). It returns  when it should return [4, 4]."
def purify(lst): nwlst= for item in lst: if item % 2 == 0: nwlst.append(item) return nwlst