Give the definition of a function $f$ from the set of lists with integer entries to itself so that the output list satisfies the following properties:

If the input list has $0$ or $1$ entries, it is returned unchanged.

If the input list $\frac{?}{?}$ has at least $2$ entries, the $(i+1)$ th entry of the ouput list $fl$ is the sum of the $(i+1)$ th and the $t$ th entry of the input list $l.$

For example,

$f[4,3,2,1]=[7,5,3,1]$

If you don't need all the cases suggested, select the entry IIIII for both values for any unused ones..

base case $1f$: $f([a])=[b].$

base case $2f$:$,f([c])=[d].$

step case $1f$:$,f([e])=[f].$

step case $2f$: $f([g])=[h].$