Human: Merging a list with a list of lists Assistant: 
Here is some code to for each index `x` from 0 to 3, append the element at index `x` of list `b` to the list at index `x` of list a.

[a[x].append(b[x]) for x in range(3)]

#Warning: this code generation is experimental. Please inspect the code for any bugs before executing.