Self re-initializing variable?

[python_user_n]

Hello,
I'm testing this snippet of code:

ld = [1, 2, 3]
ll = ['a', 'b', 'c']
loft = zip(ll, ld)
#for i in loft:
#    print(i)
print(loft)
d = dict(loft)
print(d)

If I uncomment the for loop the dictionary will be empty. I suppose for some reason loft reinitialize itself as empty variable.
I want to know if it's a normal behavior or my poor understanding of the language specifications.
Thanks.