>>> x = [2,5,7,2,9,5]
>>> y = [k*k for k in x]
>>> y
[4, 25, 49, 4, 81, 25]
>>> z = [k*k for k in x if k*k*k < 200]
>>> z
[4, 25, 4, 25]
>>> out = []
>>> for k in x:
...     if k*k*k < 200:
...             out.append(k*k)
... 
>>>