Ken Iverson’s Favourite APL Expression?
Python 2, 34 bytes

lambda l:map(sum,zip(l+[0],[0]+l))

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37 bytes

lambda l:map(int.__add__,l+[0],[0]+l)

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Python 2, 38 bytes

p=0
for x in input()+[0]:print x+p;p=x

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Python 3.8 (pre-release), 37 bytes

lambda l,p=0:[p+(p:=x)for x in l]+[1]

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