3a

Please code in language: Ocaml

The Fibonacci k-step numbers are a generalization of the Fibonacci and Tetranacci sequences, where F_i = 0 for i 0, F1 = 1, F₂ = 1, and for every j 3:

F_j = F_j-1 + F_j-2+ + F_j-k,

(a) TODO: Implement an OCaml function sum_top_k : int -> int list -> int, which accepts an integer k along with a list of integers, and sums up the first k elements of the list. If the list has length less than k, simply sum all the elements in the list (assume that an empty list evaluates to a sum of 0).